Basically, the character used "stunts" to perform feats. There were 6 different types of stunts based on each of the key character abilities (strength, dexterity, etc.).
A "Might" Stunt (based on Strength) was used for "Feats" like breaking down doors and snapping restraints. A "Savvy" Stunt (Intelligence) was used for "Feats" like solving puzzles and deciphering codes.
If the character decided to use a "Feat" then that was his full-round action (no move or attack).
The difference between "Stunts" and "Feats" was that a "Stunt" could be used as part of an action which also involved attacking and/or moving. So, for example, if you wanted to attack a monster and try to kill it, you would use a "Might" Stunt to add bonuses to your hits and damage, but then you couldn't also add an Acrobatic Stunt (based on Dexterity) to your AC that round.
"Feats" are the default skills system for the game. Basically, the rules say that you can do pretty much anything with a Feat. The GM assigned a TN (Target Number, which is exactly like a DC in 3E) to the task, and then the player rolls a d20, adds his/her stunt bonus (based on the type of Feat/Stunt being performed) and if he/she rolls over the TN set by the GM, then the Feat is successful. GMs are encouraged to be very liberal in setting the TN so that players succeed more often than not.
Example TNs from the Rules:
Easy (using a Might stunt to knock down a door) = 10.
Average (staring down an Imperial Officer with a Charm Stunt) = 15.
Difficult (running up a wall, Acrobatics) = 20.
Absurd (swimming underwater for 1/2 hour, Fortitude) = 25.
Hope that helps.