Read this article to understand how to use MJS+
On the first start, you'll find yourself on the Manager interface. On the left panel, there are mods and settings buttons. In the middle, there is the interface corrisponding to the left panel selected. In the bottom left, there is the network status (server, ping and connection). In the bottom right, the start button.
The panels on the left are：
- Extensions (mods that use javascript)
- Resource packs (mods that replace media files)
- Tools (includes the tablecloth maker)
- Settings
- Info
In the top right you can find 3 buttons:
- Open folder
- Install
- Edit (either package for sharing or delete)
After you select your plugins and choose the settings, press "Launch game" to play.