Scott's covered it very well..

But if you're a complete tyro and your breakers are as Not-marked as many I've seen:

FIRST - plug a lamp into the one you are planning to kill / turn-off its breaker;
WATCH it go out when you flip the breaker you Think you should flip.
The less you know about how house circuits work, the MORE you need to take this redundant step, IMO.

(If the present outlet is the "push wire in and-hope" type - you usually need a small screwdriver to insert nearby the wire-hole = to release that wire end, for inspection? or when replacing.)

Sometimes you can just use a pen-knife to scrape, make the wire shiny and reinsert -- til you get the replacement.

It's often a PITA to unbend then rebend old Real Copper wires around the screw-type outlets and switches; the copper is work-hardened / no longer 'annealed', thus stiff -- but they are Better for reasons mentioned.

Long-nose pliers mucho helpful in forming a small-U on the ends.
You can handle this.

(Or.. if you err on Part 3, we'll never speak to you again, y'hear!?)