bypass stock alarm for aftermarket one

Hi all. I'm new here so sorry if this has been answered previously. I have bought an aftermarket alarm system with remote start etc. My question is, am I going to able to just install this or is there going to be a conflict with the factory alarm/immobiliser? I bought the car with no key fob so have been using key entry anyway, the security light on the dash works so I assume there's an alarm/immobiliser in operation. Any info would be greatly appreciated. Many thanks. Shaun