Securing rubber mats to garage floor
Once the concrete is cleaned of all dust and oils, the rubber mats should stay in place, especially once you get a few of them down.  If you want a little extra help, I'd offer two options:

"Carpet tape" is a thin, double sided tape that's usually about 1.5" to 2" wide and can be placed on the floor under the mats.  It's will be easier to remove than other adhesive options, but it will only provide a little extra grip.

If you find you need more holding power, you might want to install some type of perimeter strip around the mats (assuming they are laid in a rectangular pattern) to make a "frame" that holds it all together.  Holding the mats from sliding out from the edges means there will be less to remove when you are done.  Rather than adhesive under the whole mats, you could glue or screw down strips of wood along the edges.  Screws might leave divots in the floor, which could be unacceptable.