Hi Guys I'm not sure if this is the right place to be asking for help with a plug in, I'm very new to after effects in fact this is my first project with it, and I have been following a tutorial for creating fireworks with Trapcode I have created a firework I'm happy with now I would like to duplicate it a few times but I can't work out how to. any help would be appreciated. I'm using the latest version of After Effect
First - Start here: Basic AE
You will end up being frustrated and end up with some very bad habits unless you learn the basics. Duplicating a layer is just one of the basics. Nobody I know was ever successful learning AE by just diving in and creating a project from a tutorial. Most YouTube tutorials I've seen are poor examples of workflow and technique so you must vet your trainers, especially in AE.
If a NLE is like driving a car then using AE is like flying an F-18 off the deck of an aircraft carrier at night in a hurricane. Possible but dangerous without a bunch of training and you have to know where all the switches are.