Hi - I'm not sure which tutorials you were watching, but when most of us add an external drive, it is NOT used to store 'active projects', those that we are currently working on.
We use the external drives for backing up project folders, and some use them for placing some of their sample libraries there (I don't recommend placing sample libraries on an external drive, for performance reasons, but for some folks they just don't have enough room on their internal drives).
Do you have enough room on your internal drive(s) to keep your current projects there?
Please explain how many drives you currently have, and what kinds of things are on each one.
Thanks,
Bob Bone