Oh and the 'scripts' folder should be in the GTA V directory.
Okay, so check that you have Script Hook V and Script Hook V .NET. Then, install Build A Mission and copy/extract the files inside that .zip file to your 'scripts' folder. If you don't a 'scripts' folder just make one, but don't call it 'Scripts'. Finally, do the stuff it says in my mod's description.
just press H then go to installed missions and you should see it there.
you mean how to turn on the menu?
Oh and I forgot to put that you need the Build A Mission mod as well.