If you want a bit of practise do the training missions first before jumping into career. That's what they are for. You can revisit them as much as you like to let you try different things.
Don't go the whole hog with manual targetting until you've practised a bit with assistance on. Once you feel confident and getting a hit is easy with the helpers, then disable them one at a time and allow yourself time to practise until you are proficient with each one turned off.
Read up on the manuals a
If your goal is full realism with manual targetting, then GWX with MaGui is the way to go mod wise.
Wilkommen zu Subsim und Gute Jagd!
