Plan out your design first so you know how many studs to get. Certainly don't want to run out. Also don't be afraid to vary types and sizes of studs. No reason to be plain-jane one type.

There's many variations of stud backing to use:

• folding prongs - just cut two slits with a knife, push the prongs through, and fold over using a flat head screwdriver or butter knife.
  

Ex: https://www.amazon.com/Nailheads-Spots-Studs-Square-Finish/dp/B008HHPS1O

• screw backs - poke (or use a leather punch) a hole, push the back through, and screw down the top. A small dot of white glue on the threads helps to lock it into place. ex: https://www.amazon.com/STRAWBLEAG-Screwback-Patches-Clothing-Accessories/dp/B09JG5Q973

https://www.amazon.com/YORANYO-Install-Leather-Clothing-Accessories/dp/B08LY8JTHB/

• rivet - these are more involved as you'll need a specific sized rivet setter (relative to the rivet), a mallet to whack, and a hard flat surface.

https://tandyleather.com/products/dog-collar-spikes-rivetback-nickel-plated-10-pack

You probably want to practice a bit on an old jacket or pair of jeans you are going to toss out.

Cycle back and post your results. I would like to see it!

Edit - don't forget to check out youtube videos. Sure the bulk are denim jackets to Nelly Furtado background music, but the technique is going to be the same.