Approach a locked door or container and select the lockpick option
Use the left stick or mouse to move the pick to a tumbler
Press the action button to set the tumbler
Watch the tumbler speed and timing
If the tumbler moves slowly, press the action button again to lock it in place
If the tumbler drops, move to the next one and try again
Repeat until all tumblers are set
Use auto-attempt if you want the game to try for you
Use higher Security skill and more lockpicks to make it easier
Use spells, items, or the Skeleton Key if available to improve success
Save before difficult locks and retry if needed