Patience; there's a learning curve.🙂
After splitting-out the desired clip, use the left-arrow button to go to the start of the clip... 
Hold down <shift> then use the right-arrow button to go to the end of the clip. The clip will be selected (blue).
Right-click in the selected area and Export selected region. Note the target folder, and choose your export settings (the defaults are often best). Click Create.
The result will be a clip that can be imported into future projects.