I need to solve the following use case:
Example: project1 > Global, project2 > RP2, project3 > RP3, project4 > Global, etc
What is the best approach to accomplish this?
Just share your blueprint to the project. Only when you have specials you need to work with constraint tags to get it placed with the correct resources. I would say just start simple and expand your blueprint and then you will find you special problems.
My question is about how to use tags to accomplish my goal.
Best is to read into constraint tags on resources in de documentation. It is a pretty wide topic. You can use it on a lot of things like storage, ipam networks etc