Hi Ronnie and welcome to the forums

Plastitol transfers are screen printed, they are not printed with a desktop printer. You place an order with a company that makes them and they send them to you, you then press them

Doing dark shirts that is your best bet for a nice product. In my opinion, there is no good inkjet paper for darks that is going to give you a professional result. Try F & M or transfer express. I think those are the most common ones here that I see, oh also Ace transfer. There is a list of vendors here
Custom Plastisol Transfer Vendors, a list, that might help as well.
Hope this helps. Remember if you order them, try to arrange your designs so you can fit as many on one sheet as you can, to save money
