Mods don't disable achievements, as long as you have killed moms heart (Endboss of Womb 2) at least once on the savefile. Kills on challenges or dailys dont count.

Quoted from the wiki:
" Playing with any enabled mod prevents any achievements from being unlocked.
If you heave beat Mom's Heart at least once, achievements will no longer be locked."

Simply press the "subscribe" button on the Workshop page. This will automatically download and install the mod. Just start your game again afterwards, and the mod will be listed in the "mods" menu in the main menu where it can be activated/deactivated.

You need to have all DLCs of this game installed! Workshop mods only work with Afterbirth+

1. Check if the mod is listed and enabled in the "mods" menu. See the question below if that is not the case.
   
2. Disable all other mods you have installed and see if one of those caused any errors.
   
3. Check if the debug Console displays any error message (How to open the debug console[bindingofisaacrebirth.gamepedia.com])
   
4. Execute the "Verify Game cache files" function in steam for the Game. Step by step guide can be found here Verify Game Cache Files [inxile.zendesk.com]

if the mod is not visible in the mods folder even after you subscribed to the mod, it could be caused by the following:

1. You dont own all DLCs (Afterbirth and Afterbirth+). All Steam Workshop mods require those two DLCs to be installed in order for them to work correctly.
   
   
2. Your Windows / Mac Username does contain special characters, that are not part of the standard english alphabet. Since the game is not able to interpret those correctly, it cant find the mods folder. In order to fix this issue, you sadly have to create a new Windows User on your computer which name only contains english characters.

The simplest way to edit the config is to use the mod "Mod config Menu&amp".

Alternatively, you can change the config manually following these steps.
Windows
1. Go to ..\Documents\My Games\Binding of Isaac Afterbirth+ Mods\ReHUD\
2. Open "main.lua" with any texteditor
3. Edit the Config file
4. Save the file
5. Play the game

Linux / Ubuntu
Same as aboth but the path is: /home/%YourUsernameHere%/.steam/steam/steamapps/workshop/content/250900/836319872

Simply change the "eid_config.lua" file found in the mod's resources folder. See the question aboth if you need help with locating that file.
Edit the Config setting ["Language"] to the language you want (for a list of supported values, look into the config file.)