Seconding dbaupp, there might be people who can consciously manage all details of the various subskills at the same time (I don’t know anyone like that though), but if you don’t belong to them it’s almost certainly far easier to learn to drive the way other people who can’t do that do: Practice until the subskills don’t require more than a manageable level of conscious attention (for many (most?) people eventually zero attention on well known routes). You could also try looking over your shoulder and imagining yourself using the turn signal whenever you walk around a corner, for example.
Seconding dbaupp, there might be people who can consciously manage all details of the various subskills at the same time (I don’t know anyone like that though), but if you don’t belong to them it’s almost certainly far easier to learn to drive the way other people who can’t do that do: Practice until the subskills don’t require more than a manageable level of conscious attention (for many (most?) people eventually zero attention on well known routes). You could also try looking over your shoulder and imagining yourself using the turn signal whenever you walk around a corner, for example.