Until SDK version 0.3.7 (October 14th 2022), there was a bug that would cause you to load into the wrong level sometimes. This has since been fixed, but requires the author to repack and reupload the mod, and by extension it requires you to redownload the new version. now it's probably more or less fine, but if you're playing a really old map, you may need to move all other levels out of the mods folder if its being weird.

• Press win + R to bring up the run box, type in %appdata% (like you're 12 and modding minecraft for the first time), and hit enter.
  
• You'll actually be one folder too deep, so at the top, it should say
  User/AppData/Roaming
• Click the word appdata, to go up a folder
  
• Double click LocalLow, then inside this folder should be the folder Stress Level Zero, and inside that folder should be the BONELAB folder.
  
• Inside this folder, open the repositories.txt file with notepad
  
• Add the URL
  https://blrepo.laund.moe/repository.json
  to a new line. (you may also add the URL
  https://blrepo.laund.moe/nsfw_repository.json
  if you want access to NSFW 18+ mods.)
  
• If you did all this correctly, your repositories.txt file should look something like this
  # repositories.txt # Put your mod repositories in here, separated by lines. # For example: # http://www.example.com/repo1.json # http://www.example.com/repo2.json # # Empty lines or lines starting with # or ; will be ignored. https://blrepo.laund.moe/repository.json https://blrepo.laund.moe/nsfw_repository.json
• Save your changes by pressing ctrl + S, and open bonelab

now at the mod station in 02 Bonelab Hub, under external, should be a list of mods!

If you prefer manually downloading mods instead of doing it in game, you can find them at https://mod.io/g/bonelab, then put the mods you download in
Dont just put the .zip in the folder, that wont work. unzip it, and you should have a folder with a name like this
(if the folder isnt named something like that, click into any subfolders that may exist until you find one with a name like that)

put that folder in your mods folder

For maps: go to the mod station in the hub, and select "mod levels"

For avatars, select them from the body mall like a vanilla avatar

For custom weapons, spawnable items, NPCs, ect, you can spawn them with the tool gun

go to the mod station, and in the menus there you can enable developer mode. restart the game, and then this adds two new options to the quick menu. one titled "dev tools", which spawns the tool gun (used to spawn and delete items, npcs, weapons, ect), and the nimbus gun (used for flying around. press the mag drop button to enable noclip with it)

it also adds a button called "avatars", which lets you select from the full range of avatars wherever you are, not just the ones on your omnitrix

If you found this guide helpful go ahead and like it, or dont i dont care i just wanna make information accessible. if you have any issues or questions feel free to comment them and i'll try to help.