Hi
As Borate suggests, put your two clips onto the sequence line..one on track 1 and the other (your cutaways) on track 2.
Track 2 is an overlay track and will cover up track 1. So at the point where you want to cut away to track 2 split track 2. Now either remove (delete) the section to the left of the split, or reduce its opacity to 0%. This will now reveal track 1.
If you play your sequence now you will see track 1 then at the split point, track 2.
Now, where you want to come back to track 1, split track 2 again. Where you want your cutaway to come in again, split track 2 once more and delete (or reduce the opacity of ) the section to the left of this split........and so on to the end of your film.
In brief, you are making gaps in track 2 which will reveal your main film from time to time.....a bit like this.....
____ _______ _____ ___ ___ ___ Track 2 (cutaways)
____________________________________________________ Track 1 (Main track)
Before starting adjust the two tracks so the soundtracks of each are in synch, then mute the one you consider to be the worst.
Nat