If you look close at your IO setup(that your screen capture shows), just to te left of each path name is a small arrow. Click the arrow and the sub-paths will show(a stereo input path can have 2 mono sub-paths). IOW, the mono paths are already there by default(if not, then the arrows would not be shown). If you cannot select a single path when you want to, odds are that you are trying to select a mono input on a stereo track. Put up a mono track and the mono paths(inputs) will show.
Another option(since there's usually 4 ways to do anything in the digital world
), you could delete all the stereo paths and only create mono input paths(the disadvantage will be that you won't be able to use a stereo input when you do want to record to a stereo track)
Last thing; since I have no idea how experienced you may be, here's a basic "rule of thumb". Use a stereo track when recording a source that IS stereo(like most keyboards or guitar boxes like the Helix) and use a mono track when recording a mono source(like a voice, bass guitar or most combo amps). And, don't fall for the mistake of trying to record an instrument(like guitar, bass, piano) to an INSTRUMENT track, because an INSTRUMENT track is made for use with VI(Virtual Instrument) plugins(like Kontact, MiniGrand, BOOM, etc)
