Find a retired local mechanic / fitter who will help.

Most tradesmen will willingly help / teach people who don't know how, but who want to learn.

No tradesmen are interested in helping people who just want a cheaper alternative to the local garage, and who don't want to learn.

FWIW over tightening fasteners is by far the most common mistake the amateur makes. The seond commonest mistake is forcing something that doesn't want to move, often because there is still a hidden fastener or something that needs to be removed.

After that you get into cleanliness, sadly even mechanics are rarely good enough at this, every single fastener you remove should be put in a vice (by the head ONLY) and have the threads cleaned up with a wire brush etc, all mating surfaces thoroughly cleaned, all parts cleaned and washed.

If you're a smoker, stop and think and smoke in between minor operations, if you're not a smoker, still stop and think, and look at the job, even experienced fitters notice things this way.

Above all, don't rush it, treat everything like it is made of glass and very valuable, you won't go far wrong.

Face facts, your vehicle is off the road, it's gonna stay that way until fixed, make alternative arrangements so you aren't under the hammer to git r done.

Put fasteners back where they belong, eg timing cover fasteners, clean them, then put them loosely in the right places in the block, that way you don't lose them, put the wrong ones in and cause more damage, or forget any parts when assembling.

it's NOT rocket science.