As stated before the game is very similar to minecraft. To play you need to collect resourced.
Movement is WASD
Use your mouse to look, click to perform an action.
To Auto-Click (for farming) press E

Here are items and things you'll see in the game and descriptions of what they are and what they do.

Tree


Hit them to collect Wood, preferably hit two at once because wood is used in like everything in the game.

Stone


Again hit them to collect stone, you can also hit stone that you place down to collect stone however those are smaller and you need 100 previously farmed stone to place down the 1 single stone block you get in the game. Stone can be used in windmills spikes and stone walls.

Apple Trees


These are extremely important, collect from them right away, players will try to kill you, you can eat apples, or later cookies if you choose the option, to heal yourself a bit. Always stock up on food, never stay low as you can be raided.

If you wanna make a team or join one, click the team icon, it'll look like this.



Look for the team name "TFM" if you wanna join the Transformice Team and click join and whoever the team leader is at the time will approve you.

From then on out you can come into whatever base the team is making or defending at the time.
If you want to make a base, get 100 stone and look for two trees that are close enough to hit both of them in one swipe, place a stone block between them. Make sure the two trees have an apple tree near by or find another location. Then just build up walls and such.