You absolutely need the proper tool to install the riv-nuts. This is an affordable model from Amazon.

https://www.amazon.com/rivet-thread-...68342113&psc=1

I used aluminum riv-nuts in my door frames with a drop of red loc-tite on each insert to keep them from turning in the frame. I did put a tiny amount of low strength (purple) loc-tite on the screws to keep them in place (and to keep them from corroding) because they should not be more than finger tight.