rear bench seat

how do you pull out the rear seats out of a 01 silverado ecsb i see straps one on the top middle and two on the bottom ends how do use thoses to pull out the seat??? or do i have to unbolt it first???

to get it out there are 2 18 mm nuts on drivers side under a small plastic cover and 2 18 mm nuts on passenger side near the jack and then 1 18mm bolt against back of cab attached to a cable to the back of the seat. this is how my 02 is bolted in. the 2 straps that are hanging down are just to fold the seat up and thats it. hope this helps