Was a long day didnt have time to draw my own but found this online so will use it to explain lol.
I have common pvc plumbing gaskets on the top slightly larger than the tubing that comes from my pump allows me to attach a reducing coupling.
The spray bar is a standard pvc pipe with holes drilled along it.
I personally do not use any carbon.
I keep some on hand in case of some chemical going into the pond.
You can buy online filter media of any size and cut to size. Or use something that matches an available size.
First filter is like a pre filter catches large debris like leaves.
Next is a finer sponge.
Next is an even finer sponge.
Next is a micron filter pad.
Last is my layer of bio balls.
Now another pvc plumbing gasket for my out.
Keys to remember pressure builds on the filter system each time you reduce outflow.... So try to keep your outflow at least as large as the intake.
Buy a bacteria starter from local pet store. Also a dechlorinator.
When cleaning filter media always use pond water not tap water.
They also sell many good pond filters on amazon that are not badly priced just stay away from submersible ones, they dont work well and a pain to clean.