When to add LR??!! HELP

[dekay]

I'm starting to get very confused now. Article on reef central saids I need to add my LR when ammonia and nitrite reaches undetectable levels while the article on www.liveaquria.com tells me to just dump them in to cycle the water. So when do I put the LR in? Is that why some of the life in the LR I just bought started to die (due to ammonia & nitrite)?

FYI, after I mixed my salt water, I placed some cocktail shrimps in there to spike up the ammonia. After like 3-4 days, I threw in the sand and LR. Should I wait before I put anymore rock in or is now the time? There's still traces of ammonia in the tank btw, I don't remember the reading though.