Oh man... this was me nearly two years ago. I plumbed my 1st system.
1. Plan Plan Plan!!
2. Get extra parts...trust me you will need them
3. Dry fit everything before you glue, and mark the area. This will make fitment a breeze later, when you glue.
4. Be prepared for leaks. Not the end of the world, but be ready to cut pieces out and replace
5. Plan for the future! Meaning build a manifold to easily add future equipment. You may not use it immediately, but super convenient when you do.
6. Make sure your pump can deal with applicable head pressure. Each 45 or 90 degree adapter will add additional head pressure to your pump.
7. Use lots of unions!!! Or Union ball valves
8. Plan!!!
Here are my results:
This was before I added a UV to the system, see number 5.