Both dominant chords are “borrowed” from the major key due to their strong tendency to resolve to the one chord.
Notice how it starts on the one chord which can then lead to any other chord from the key.
From there it’s just a matter of finding your way back to the one chord using the many possible routes.
The Minor Key Progression Cheat Sheet
Let go ahead and give it a try. Use these diatonic chords from the key of A minor to write a few chord progressions.
If you come up with something you like why not YouTube it and drop the link in the comments below. I’d love to check it out.