The big deal is to have a developer profile, actually.
For that, you need to have an iOS developer account (if you are a student, check if the place you study at can give you one for free. Else you’ll have to pay 99\$/year).
With that, go on the provisionning portal, and create a certificate (which is used to sign the application) and install it on your computer. You also need to add the device to the portal, with your UDID.
With both the certificate and the device registered, you can create a provisionning profile for your application (or just use the wildcard one). Be sure to check that the provisionning profile App ID match the one in your Info.plist, else XCode won’t accept it.
Those steps are very confusing the first time, hopefully this will give you an overview of what you have to do. I recommend reading the documentation on iOS provisionning portal, which gives very detailed step for each of those.