It may not come as a surprise that the default dice mechanic will be "Kursk Dice" also known as the "Man to man" option in the 3rd edition rulebook.
Essentially, you will roll your handful of action dice and assign each to a single figure or a group of up to 3, who will then act according to the die issued.
1's will Scurry, allowing them to move without attracting reaction fire.
6's will Quick Fire, allowing them to shoot without attracting reactions.
Other dice will move and fire normally, but will cause reactions to be incoming.
In a typical squad-level fight, you will have 3 action dice but it can of course be scaled up for larger actions. This means each turn moves quite quickly.