New! starting out a SW Aquarium

[Dragon780]

Hi everyone, im new to SW and new to CR

i was wondering is it safe to get used live rocks, and am i able to just put it into a new tank to cycle, i have a 65g tank with not fish or critters, have a few live rocks, is it ok to put used live rock in there to cycle, and during the cycle period, doesnt the rocks create alot of ammmonia? is there anything i need to do, or does the cycle itself takes care of it and it will soon be safe to add fish and corals?

and is it ok to use tap water and use water conditioners

thank you for all your help in advance