Kinda like this...
Let's go back to the "Cycle"...and how the bacteria multiply and convert waste...and create a safe and stable envrioment for your fish..
Basicly you start with your tank, salt, and water...a "sterile" envrioment...
"IF" you add fish...the waste they produce (ammonia) will build up to toxic levels and kill them...That would be a bad thing...
However there are a couple forms of bacteria that come into play here to "convert" this waste to less toxic forms..
The bacteria is introduced from the live rock and live sand you added...
The Nitosomas bacteria will "eat' and convert the ammonia (fish waste) to nitrItes..which is less toxic than ammonia, but still a bad thing...
The more ammonia produced the more nitrosomas bacteria will multiply...
BUT...until there are enough of them..the ammonia level will rise and possibly become toxic (deadly)...
Eventually there are enough of them to convert the ammonia as fast as it's produced and the level stays at 0...
That's the first part (or peak) of the cycle..
Then you have all this nitrIte floating around...also toxic to lifeforms...
But there is also a nitrobactor bacteria introduced with the lr/LS...and as their populations increase...they "eat" and convert nitrIte to nitrAte ...which is much less toxic (unless the levels get too high)...
Same as the nitrosomas...untill nitrobactor populations increase the nitrIte levels will increase..then decline to 0 as the populations can consume as fast as production...
That is the second part or "peak" of the cycle....
Until both ammonia and nitrIte levels drop to 0....it is not a safe or healthy envrioment for your fish...
Then nitrAte levels will increase and build up but they can be reduced through regular partial waterchanges and other "de-nitrifying" means...
So, how do you "feed" the bacteria and build up these populations of bacteria without subjecting fish to toxic levels...??
There are a couple ways to do it, and some of the "food" is already coming from the decaying matter off the LR...
A"gentle" way to do it is to start "feeding" the tank flake food...(just a small pinch each day) "AS IF" you had fish in there..
Feeding the invisable fish....
As the "small" amount of flake deteriorates..it produces ammonia, which feed one bacteria which convert an produce nitrIte, which feeds the other bacteria, which convert and produce nitrAte...
As their populations grow...eventually they can support a fish or two without the levels rising by converting waste (food) as fast as it is produced...
So...you'll need "test" kits...Ammonia, NitrIte, NitrAte and you might as well get a pH kit to test...monitor...and follow the "cycle" through it's "peaks" and drops to 0..so you'll know if/when it's safe to add fish...
I would suggest getting the kits..testing and recording the levels of ammonia, nitrIte and Nitrate (if present) in your tank...Then start feeding the invisable fish and continue to monitor levels...
In a couple weeks you should have gone "through the cycle" and have a safe envrioment to add your first fish...