Don't have the 6e rulebook, but I would suggest you check out the "Prone" condition modifiers....
If older editions, being prone fucking sucked! Defense actions were limited (later changed to a DP modifier), attacks against you had bonus dice, movement was limited until you stood up (so getting into cover was harder)
In 4 and 5e, knocking someone prone was mostly a team taxtics thing, because of the limit of a single attack/rnd.... which meant a team's first attacker would try to knock a target prone, thus limiting that target's defense and attack dice pools, while adding a situational bonus to the rest of the team....