Aquarium Bulb Placement

[LNat]

I have an AquaticLife T5 HO and Lunar Light Fixtures and just received replacement tubes. Any recommendations on placements?

I purchased the following:
(2) 48" SUPER ACTINIC T5/HO 54WATT
(1) 48" 54W T5 HO 10K BULB
(1) 48" 54W T5 HO PURPLE BULB

First time replacing the bulbs and I'm confused. Your help is very much appreciated.

Thanks.