How merge a branch into main?

I have been using the plugin and it's great to be able to use git within the editor.

I don't use Github or any other remote git service. I use git very simply. I have my main work on 'main' and make branches to try out ideas, features, etc, and then merge these branches into main when I am finished.

I made a branch using the plugin to do some work, expecting I would be able to merge this branch into main but I can't find a 'merge' action.

I read the wiki and nothing is mentioned there.

Am I misunderstanding how merging is performed using the plugin, or is merging not possible using the plugin?