Chevrolet 2002 Venture Owner's Manual page 22

Adjusting the Bucket Seats
There are two adjustment levers on each seat to adjust
the seat forward or rearward.
One is located below the center, in front of the
bucket seats.
1-16
Lift up either lever and slide the seat forward
or rearward.
Release the lever. Push and pull on the seat to make sure
that it is locked into place.
The other lever is located on
the rear of the bucket seat.