I just went thru that today. Can't say I can get you through it, as I had computer issues that I had to over come, but I can definitely try to help. Phone call might be easier to walk thru. Do you have an account set up in Cricut Craft Room?
There is a port on the back near where the power cord plugs in that takes a USB cord. But I believe you have to have a 3rd party software to make it work. Not sure about that. I purchased Sure-Cuts-A-Lot before they got sued, so I can use my computer. I'm not sure who still makes one compatible. I think Cricut sued them all.