Once you download and open the game, start a new run and choose any starting options you'd like to have. Default starter units are quite balanced for beginners, you may want to only edit main character, profession, and your starters' traits. Once you make it through story/setting, start exploring town to encounter new NPCs and events. Map (default hotkey M, or Right Mouse Button when other screens are closed) can allow for easier navigation between locations in town, and show you what places have new events by highlighting certain locations with yellow.
Before venturing into a portal it is best to bring along starting companions with equipment that can be purchased from the shop, hotkey (S), or gathered through town exploration. You need to assign your characters to your party at home first and then proceed with equipping items on them via Prep. Party option, hotkey (Q), which is located at the bottom of the screen. Any characters with healing abilities can help with portal exploration greatly. If you chose a PlantGirl pick as a starting character, with luck it might have Rejuvenate skill. If you struggle to keep your team alive you can restart your game to pick Doctor as your starting profession as this will make you able to heal injured party members and save on infirmary or town doctor costs. You may also want to gain certain combat experience with your team before portal explorations by picking up some easy arena fights, also earning solid amount of money, which you can spend on buying even more gear.
Choosing low hostility portals at start is of the utmost importance: as low a number as you can get, primarily below 3. Portals destabilize in a short period of time unless you pay forth some gold and crystals to maintain them. Once you have stabilized the portal, it will remain until you manually destroy it. You don't need to pay again. The maximum number of portals you can stabilize is capped at 5 from the start and you start with an already stabilized portal of hostility 1. The hot key for portal menu is (E).
Once within a portal it is important to be mindful of your carrying capacity. Try not to get overburdened, which occurs when more than half of your total carrying capacity is filled, as this makes you spend twice as much time for movement. If you harvest too much and cannot move, drop items or resources from your inventory and continue onward.
If your team has been damaged or is low on mana, set up a camp for a while and set your wounded characters to 'Rest' and your mana drained characters to 'Meditate'. You can also encounter certain tiles and events which can help you to maintain party resources. While camping in a location that is unprotected, like anywhere outside of a hut, you can be ambushed while camping. Try to keep the ambush chance as low as possible to avoid risking an attack while your characters are still weak by setting some of your party on 'Guard' duty. The higher guard character powers are, the more effectively they will prevent an attack. Having no characters on guard duty means that if an attack happens, it will be an ambush, where your party begins with only 1 AP each, and enemies are scattered among your units rather than on the other side of the field. Nearby passing enemy groups may end up stumbling onto your camp, or notice you and attack on purpose if your group stealth value is poor, which will lead to battle. If you choose doctor as your profession, your main character duty can be set to "Doctor", which will increase the healing of all other party members who are resting.
In order to make your character stronger in long term run you may want to level up your skill tree. As Evolution and Creation MC, you must perform rituals with species who you've not already performed a ritual with and spend newly earned points under "Change" option at the bottom of the screen in order to increase your character powers (The hot key for skill menu is (C)). To perform a ritual, select gender-appropriate character (any for Evo in her futa form and futa/male for Creation) by clicking on them at home and select Ritual button at the bottom of character screen. Only pure species and their hybrids will count as valid for gaining skill points. Doing a ritual with a species which you have already done a ritual with will only grant as many points as the genetic max level difference between current partner and the former partner of the same species which you had ritualed with. Druid does not evolve through rituals, but instead increases his own powers through combat experience, gaining new abilities in one of 6 schools which you can select as leveling focus.
Eventually you may run into issue of having no food for your team nor money to enter a portal or buy anything in town. There are multiple options for sustaining those resources, such as assigning your fellow characters to hunt/fish whenever they are at home (done through character details page), gathering food and herbs in portal explorations, or fighting in arena and performing brothel shows as your character to earn some money. Placing extra trained units in the Brothel is a good passive source of income.
Crystals will be needed early for a multitude of reasons and one of the ways to obtain them early is by breeding your characters to produce eggs. The eggs will be stored at the farm, hotkey (F), within the hatchery. Destroying an egg, either incubating or in storage, will grant you a crystal. Another way to obtain crystals is to travel through ocean portals and gather underwater crystal deposits. This method is more advanced, but it rewards larger amount of crystals in a smaller amount of playtime, at a cost of stamina. This method will also take a large amount of in-game time unless you have a water or flying mount which can carry you and your team. A unit with any of the mount traits makes all units in your party who are at least one size smaller than it move at its speed over the terrain the mount is proficient at. Another option is for you and your whole team to be able to swim or fly to avoid water movement penalties.
If game still feels overwhelming or there are certain unclear things that you'd like to get explained feel free to join official discord and ask any question in #help_support_tutorial_etc channel.