Need some help with training players.

I'm kind of a starter manager here. What I am doing after a match is to train players by selecting positions as a whole, for example, I'll be training Defence as a whole by selecting defence drills. And and also that is accessible to train players individually.
What is more convenient? What is more practical? Or if they depends on anything, what are they?
Can u guys please hep me out.
-It is lvl 1 club
-69%quality and 17.3 quality value
-formation :- def 4(v)
mid 4(straight line across the field, ml and mr attacking mentality)
and st 2
Mention if any information is missing

I believe you will need Niko's guides and tutorials. The man explained everything in-depth. Worth the search.