BTA! requires mods made specifically for it. Mods made for b1.7.3 or other versions of Minecraft are fundamentally incompatible with BTA!
How to get started:
- Download the Babric instance for MultiMC/Prism Launcher. Make sure to get the zip labeled "instance" (not "server") from this URL
- Drag and drop the zip right into the main window of your launcher
- Find mods from this list that you would like to add to BTA! Collect the JAR files
- Click "Edit" while the Babric instance is selected in your launcher
- Select the "Mods" tab from the left hand side of the options
- Drop the JAR files for your mods into this menu
- Enjoy playing modded BTA!