Yes seen a few of those videos as well.
In essence though its a simple as
1) Depin According to LT1SWAP site
2) Route and lengthen according to taste
3) Join the wires that need constant/ignition +12v to a fused block control like
https://www.bp-automotive.com/produc...rness-mod-kit/
Then for AC/Fans later ....... just use a seperate harness or extend existing harness etc.
Isn't fan controlled via PCM also ?