Don't worry, have a bit of faith in yourself. As with most things, there's going to be a learning curve. Just take it step by step and ask dozens of questions in here. We all had to start somewhere, and the help I've had from this forum has been second to none.
I'd suggest, as a first attempt and seeing as the printer is currently set up as a sublimation printer, to simply install it and try a printout without an ICC. Results might not be great but it will check if everything is working and give you an idea of the process. If you have an old white 100% polyester garment or some white 100% polyester material lying around do some test prints and press them (try 180 to 190 degrees for 60 seconds as a starter).
Note that sublimation requires a polymer to be present, so all substrates, mugs, aluminium, coasters, jigsaws etc must be bought as sublimation blanks and will be coated. Cheap white mugs from B&M for instance won't work. Fabrics need to be 100% polyester and white or very lightly coloured. Wherever there are white parts in your design they will appear as the colour of the garment. Also, garments with say a 65/35 poly-cotton mix will print ok but on first wash will appear faded due to the reduced polyester present in the material. However, this can still give a nice retro look to certain designs.