to use the @give command you have to type in to chat(does not work on servers unless you are admin) @give first letter of your username to your full username (must be in order)/(the id of the item to find ids look it up on the internet)/amount (optional but if you dont put an amount you will only get one)

for example: @give mega_pooper2580/253(alicepack id)/1

if this does not work tell me what you typed in and what operating system you are using(i use mac so i dont know a lot about linux but windows should be the same)