Yep, a 20,000 lb. strap is the usual strength for a Jeep-worthy strap, that 5500 lb. strap is meant for things like ATVs. Definitely make sure to use only straps with sewn loops and never with steel hooks. 5.5K lbs. may seem adequate but it's not... especially since some recovery situations require you "jerk" the other Jeep out of its stuck situation. The proper recovery straps are called "snatch straps" and are somewhat stretchy to absorb the shock when that type of recovery technique is required.
Straps are connected onto frame mounted tow hooks that you must bolt onto your Jeep using Grade 5 or Grade 8 (like shown below with six little tick marks on the bolt head) bolts. Most any 4x4 shop will have suitable tow hooks. For the front, the hooks are bolted on top of the bumper. Their mounting bolts replace the top bolts that hold the bumper in place which pass through the bumper to the frame below.
For the rear, tow hooks also attach to the frame like shown below. One mounting bolt hole exists, only one more must be drilled. The rear tow hook bolts only pass through one side of the frame and the nuts and bolts go inside after being inserted into the frame from the bottom through a slot that is already present. Do NOT drill the bolt holes though both sides of the frame for the rear tow hooks and put the nuts outside of the frame. Doing so will squeeze the frame together and start the two sides slowly collapsing inward towards each other. Nuts and washers inside the frame for the rear.