Hey @S2112ify!
I’d recommend checking out the Getting Started guide, and specifically the section about Coding with Wix Studio. The resources there should set you on the right path - About the Getting started category
In the meantime, Velo code is added to a site via Dev Mode in the site editor. It’s worth noting that wix-users is a deprecated API and may no longer work. I’d recommend updating it to use the wix-members-frontend API - Introduction - Velo API Reference - Wix.com.
This answer here should set you on the right path - show a button based on member role - #2 by jonatandor35
Hope it helps 