When I want to split the screens I usually do one of the following:
- open new window with: Ctrl+Shift+N
and after that I drag the current file I want to the new window.
- on the File explorer - I hit Ctrl+Enter on the file I want - and then this file and the other file open together in the same screen but in split mode, so you can see the two files together. If the screen is wide enough this is not a bad solution at all that you can get used to.