Opening the console is easy. There should be a key on your keyboard that has this icon (~) Press that key and the console will open. You'll know you did it because a black bar will appear on the bottom of your screen.
If it works your game should have this

Here are a few commands that change your character.

-Ghost: Allows you to fly through things, you can use this to explore the whole basement.
-Fly: Makes your character have the ability to fly (can't go through things).
-Walk: Makes your character normal again, use this to get out of fly mode or ghost mode.
-Changesize: Put any number and your character will change size. If you go higher than 100 you will automatically win and hit the basement.

Here are some commands that change maps, use open or servertravel for these to work

-Level_1: Resets the level.
-Intro_Map: Sends you back to the main menu.
-Main_Menu: It's the Alpha 1 main menu but a little bugged, no you can't use it to play Alpha 1 in Alpha 2.
Neighbor_3: A large house which was used for some screenshots and is very dark. If you use this one turn shadows off to see what you're doing or find a flashlight, another method to see will be listed later in the guide.
Lakewater_example, Oceanwater_example, Translucentwater_example: These have no relevance to the game, they just came with a water engine the devs bought.

Some commands that alter the map.

-Destroytarget: Using this deletes anything you're pointing at. You can use this to get past the borders and get out of bounds, the neighbor can't chase you and if you delete him the game crashes.
-Summon: There is a long list of items you can summon in here, I will list all the ones I am aware of.
Bp_Cupboard_C (This is what you hide in, yes summoned ones work.)
Bp_Door_C
Bp_Doubledoor_C
Bp_Sosed_C (this is the neighbor, summoning him will crash the game.)
Bp_Tomato_C (Yes you can summon a tomato, but it doesn't function like a tomato at all.)
Directionallight (summons a light, can be used to light up the neighbor_3 house but you'd be better off disabling shadows.)
Bp_Lockpick_C
Bp_Bed_C (summons the neighbor's bed)
Bp_Rifle_C (it's the gun)
Bp_Key_C (summons a rusty key, it can't be used on any locks.)

Some commands that change the graphics and performance of the game

-T.MaxFPS: Set the fps to whatever you want
-R.setres: Set the resolution to whatever you want (Ex. 1920x1080w, w means windowed)
-Gamma: Set the Value to anything from 1-5
-T.motionbluramount: using this you can set the motion blur, for it to be visible make sure post processing is on, also avoid going higher than a value of 1 (0.5-0.7 is best)
-T.motionblurmax: using this sets the limit of motion blur you can have, set this higher than your amount

Note: The following commands in this section can be disabled or enabled by using the command multiple times
-Show Deferredlighting: Shows deferred lighting
-Show Bloom: Shows bloom.
-Show Bounds: Shows the boundaries of the game and hitboxed
-Show Fog and Show Atmosphericfog: These 2 work great together, Using them once disables the fog and here's a video I made almost a year ago showing how the game looks without fog

These are just some bonus commands that I thought would be cool to share

-Restartlevel: Resets to the last checkpoint.
-Teleport: Teleport to whatever you're looking at, doesn't work with all objects.
-Slomo: Change the number to whatever you want, 1 is the default speed, here's some really old gameplay of mine at half speed

That's all for this guide! If you enjoyed it feel free to give it a like (or not, I don't really care if you do or not cause I can't force you to) and have fun messing with these commands! I might update this