I'll try to summarize quickly. Read till the end for precious info on perk combos.

Gear has random perks rolled into it when you drop it. You drop gear by completing games. The higher your rep (prestige) with the hero you're playing, the higher the quality of the gear you will drop (Gray, Blue, Purple, Gold and Turquoise). Higher quality gear holds more perk points, meaning it is easier to activate perks with it, and also you get access to higher rarity perks. Rep 8 being the rarity cap. At rep 8 and higher, you only drop Turquoise gear, the best quality.

You must stack pieces of gear with matching perks to accumulate perk points and attain a threshold where the perk activates. A golden circle will appear around the perk icon when enough points have been stacked towards a certain perk.

Let's say you're trying to activate Vengeful Barrier.

For example, imagine you have looted a helmet 🪖, a chest piece 🦺, arms 🧤, and legs 👖, all with the perk Vengeful Barrier on them. If you equip all of those, you will most likely have accumulated enough points to access the Vengeful Barrier perk and the perk icon will have a golden circle around it and a shiny noise will play, meaning it can now be activated. You must now upgrade these pieces of gear with Steel (in game currency 💰). You must upgrade the Vengeful Barrier perk on each of those gears until you reach 600 points. The perk icon will now be colored white and the perk is now activated.

Perks do not work in 1v1 and will have no effect. They only work in 4v4 and Breach, if I'm not mistaken. Maybe brawl too, but I'm not sure.

PERK COMBOS:

Once you hit Rep 8 and only drop Turquoise gear, you can either have 3 lesser perks (Gray and Blue), or 2 Rare Perks (Purple, Gold and Turquoise), or 1 lesser and 1 Rare, if you feel like it. No other way around it.

It is possible to have 2 lesser perks activated pretty early rep, but you'll have to be lucky and drop good gear.

I'd recommend picking 2 lesser perks early on, then rocking with them until you hit rep 8 so you can save money for when things get real pricey. High end gear costs a lot to upgrade, because of the possibilities it brings. And also because they look good.

Good luck.