Important! Vim indent without tabs. Example to indent 4 spaces.
:set shiftwidth=4
:set expandtab
5>>
And to show existing tabs as 4 spaces wide:
:set tabstop=4
And to change cursor behavior on backspace when expanding tabs:
:set softtabstop=4
But you probably don’t want to do this, in order to make existing tabs stick out as incorrect.
To stay simple, you want to do this:
:set tabstop=4
:set expandtab
There’s also autoindent and smartindent.