Below are the steps to follow to mount a foldable chair on a seat bench:
Place a rectangular aluminum tubing in between two seat benches. This will create a sturdy frame where the foldable chair will mount.
Drill holes in the benches to correspond to the holes located on the bottom of your foldable chair.
Lastly, bolt the chair to the benches. Tip: Using wingnuts makes assembly and disassembly easier and faster.