https://warframe.fandom.com/wiki/Circuits
A lot of things in warframe necessitate consulting the wiki unfortunately. You eventually just pick this up anyway. :)
in 3 steps
Choose the game that interests you and play itfor free.
Every game has some quests for which you will receive Soul Gems.
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
You know that on Gamehag you can get real rewards for free, right? Join us, complete walkthrough and get your chest!
Sorry if I sound like a noob but how do you get circuits? I got one on accident but I don't know how.