Yay! Another TL550 owner!
But it seems that fishy and HD have already filled you in with what you need to know so I'll leave you in there capable hands!
One thing I will say tho. On one of your picks you have a piece of live rock with a considerable amount of cyano bacteria (that red stuff) that is due to lack of oxygen which means there is not enough flow getting around that area.
When you get a powerhead best to mount it on the back wall facing toward the glass at the front as that will give you a good spread of flow around the tank. Then use the spray bar to agitate the water surface as this will help with gas exchange as well as help maintaining your ph.
The UV steriliser is a load of crap so best to remove it completely and run the return pump pipe directly to the spraybar. No modification is required for this just simply unplug the uv from the pipe and spraybar and push the return pipe directly onto the spraybar.
Are you running the existing filter media in the chambers? ie bioballs and ceramic rings. If so then best to remove them as they will become nitrate traps and just run activated carbon and phosphate remover in separate media bags.
Also in chamber 4 under the skimmer you will find a huge piece of filter sponge. This will need removing as that will be caked in detritus. Either rinse it out in plain RO and place it back in or discard it.
I cut mine down to a quarter of the size and placed it in chamber 3.
Good luck with your tank mate. Theyre great little nano's and you'll have loads of fun with it.
Ps - they're very easy to modify/ upgrade components too!