I am totally new to all this, so maybe my answer is too simplistic, but I’d say you just copy the complete FCP X bundle.
Open FCP X, CMD Click the library and click Reveal In Finder.
Then in Finder copy the bundle over to the new computer.
If you have ‘managed Media’ then that is all you need to do.
Managed media is where, when you imported the original clips, you imported them in to the bundle.
if you left the original media on another drive, then you will have to copy the original media over to the ne machine too, and possible re link to it when you open the library in the new computer.