First off....
Second.... Seems like you're off to a good start. But you prob have a while before you will be able to place any fish or livestock in the tanks. Is there any reason why you chose to setup you system like this? If you DIY the tanks why did you create a larger tank? Also if you want to go ahead and start cycling the tank you can use 1 - 3 cocktail shrimps and throw it in the water once you get the live rock, as when it starts to decay it'll release ammonia and start the cycling process. You will eventually see a massive ammonia spike, followed by a nitrite spike, followed by a nitrate spike similar to a freshwater cycle. Please wait till all the above mentioned return to 0 before placing any livestock in the tank. But other than that looks like your one your way.