Hi and welcome
The hydor power heads are ok and Jacob ones are good for the money and controllable.
Get a controller for the heater, the little stats on the heaters arnt very good, simply aquaria do a good one or you can build one your self if you have the skills.
The cycle is you use a source of ammonia then the bacteria grows and eats it wich produces nitrire, then bacteria forms eats the nitrire and produces nitrate, once you have no ammonia and nitrire readings your tank is cycled.
I don't know why it's labelled live, it's only live if it's wet in a tank at the lfs.
If you buy wet live rock it will already have bacteria in it so it will be a short cycle.
Get your self the test kits for ammonia, nitrite and nitrate. Salifert or Red Sea are good but not api.
Rock structure wise acrylic rods and nyos reef cement might work.