Use Ctrl-4 to open the LaTex prompt (or Cmd-4 if you’re on a Mac). Open a centred LaTex popup using Ctrl-M (aka Cmd-M). If you’ve written some maths in normal writing and want to turn it into LaTex, if you highlight the text and then hit the LaTex editor button it will turn straight into LaTex.
Heads up, we support latex :)
https://www.lesswrong.com/posts/xWrihbjp2a46KBTDe/editor-mini-guide