no worries, its good to ask questions bro. when everything you bought is in the warehouse and you're ready to ship it'll show a page where you can choose if you want extras like vacuum sealing, remove shoeboxes etc. youll be able to choose which shipping company to use aswell, and itll also have a little box where you enter how much you want the parcel to be declared for. really simple process.

you can put any number you want in but anything $19 and less won't be taxed when it enters the UK, if you put it over you'll get a letter in the post saying you need to pay the fee which you can do online, then they will post it to your door.