At the time of writing this (Editor 6.0), there are 4 big buttons and 3 small buttons. The 'New item set' and 'Edit item set' are the most important ones. The only purpose of the editor is to design item sets and to generate the files needed by the plug-in. The plug-in can use only 1 item set (at the same time), so most people will only need 1 item set. As the name suggests, the 'New item set' button will bring you to the item set creation menu and the 'Edit item set' button will bring you to the item set selection menu where you can choose an existing item set to edit. If you are using this for the first time, you should create a new one because there is no existing one to edit.

Then we also have the 'Combine item sets' and 'Exit editor' button. The 'Exit editor' button simply closes the editor (it does exactly the same as just clicking on the cross at the top-right of the screen). The 'Combine item sets' brings you to the combine info menu. In there, you can select 2 item sets to combine into a single new item set that will contain the content (textures, items, recipes...) of both item sets. Most people will find no use in it, but it would be useful for working with multiple people on the same item set: everyone creates a part of the item set and you combine them all in the end.

Finally, there are the 3 small buttons. Two of them are about the invite link to the discord server for this plug-in. The 'Open discord link' button will open your 'default' browser and make it visit the discord invite link url. The 'Copy discord link' button will copy the discord invite link url to your clipboard, so that you can paste it. Finally, there is the 'Click here to open the tutorial' button, which should open the first tutorial (the one with the ruby item and tools) in your browser.