wiring is an intimidating black art until one tries it from scratch.
it does indeed take lots of time and concentration to do it, but is very gratifying when completed, with the added benefit of you being able to trouble shoot it when/if needed.
the only thing i might add, is make sure you have a good crimping tool that matches your connectors and terminals. a couple of practice crimps to make sure you make solid connections is recommended if you are not sure of yourself. don,t feel bad, i do practice crimps myself if i haven't used a particular crimp tool for a while, although i have wired many vehicles in the past 50 years or so.
marine heat shrink tubing is better than the normally available stuff, in that it has sealing glue that is activated when you shrink the tubing. you might consider this where moisture may be a problem or concern.