Copy-past, mostly.
1. Copy zscript directory to your mod. If your mod already has zscript directory, move the contents of my zscript into your zscript. If you want the code to be extra tidy, put Lazy Points code into a subdirectory.
2. Rename zscript files so they have your unique prefix instead of zc_. Putting files into a different directory also works. This is to ensure that file paths are unique and won't clash with other mods.
3. Inside zscript files, rename all classes so they have your unique prefix instead of zc_. Find and Replace heavily recommended. This is also so classes won't cause conflicts with other mods.
4. Create top-level zscript lump where you define version and include all files from point 2.
5. Copy the contents of cvarinfo.txt to your cvarinfo lump. If you don't have one, create, or just copy the whole lump.
6. Inside cvarinfo, rename cvars so they have your unique prefix instead of lp_. Again, to prevent conflicts. Search for renamed cvars in ZScript files and rename them there too.
7. The same for keyconf.txt.
8. mapinfo.txt - if you don't have one, just copy mine, changing prefixes for classes there for yours from point 3. If you have mapinfo lump, add classes from AddEventHandlers there.
9. menudef.txt - again, copy contents or lump with changing prefixes.
10. Copy copying.txt to your mod - technically, not required, but it's a license for Lazy Points.