A couple things:
To format (make “pretty”) all the code in a given file you can use Shift + Alt + F on Windows. See this answer for more information.
To adjust the user settings for tab size or to insert tabs as spaces, etc. you can edit settings.json (Ctrl + Shift + P then type “user settings”). You can then manually add/edit:
// number of spaces for a tab
"editor.tabSize": 2,
// insert spaces when pressing tab
"editor.insertSpaces": true
I believe both of these settings are overriden by "editor.detectIndentation" so you may have to look at that too.