Its not easy to get my head around for sure!

You might find that you can do what you want in MoreCore without any actual coding.
Most of these rolls are already supported in MoreCore from the character sheet and you can pull stats into the rolls to in many cases using Roll Parameters.

Otherwise if you are coding something new you might look at the Ruleset Wizard. Its a 3rd party tool that can make a lot of these things much easier to do. You will still need some Lua but it helps with a lot of the steps involved.