The movie here just shows the cover in action.
Step 1: Architecture
1) The roller.
2) The holders or stands.
Normally, the stands will go at the far side (or "back") of the pool.
Step 2: Materials and Tools
(2) 10-foot drain pipes (approx $8 each)
(1) 8 foot 2x10 board (approx $10 each)
(2) 8 foot 4x4 fence posts (approx $10 each)
(1) 4 foot 2x4 board (approx $2 each)
(1) box o' 2.5 inch deck screws
(4) Long L or 90 degree shelf brackets
(1) Roll duct tape
(1) Roll tread tape
(1-4) Glasses Chardonnay (just checking if anyone is reading this)
(optional) 4-8 pieces of 12-16 inch rebar
1/8 inch drill bit
7/8 inch drill bit
Box cutter/sharp knife
Step 3: The Roller
Note that the pipes here have a built-in "coupler" that allows you to sort of put them together in series.