All BlackBerry services are available on devices running BlackBerry 10 automatically without having to activate BlackBerry Services in My giffgaff.
If you were already a BlackBerry user before but are not using it anymore then you can deactivate BlackBerry Services, as it is not compatible and would prevent you from buying a goodybag should you need one.
Setting up your email address on BlackBerry 10 is very easy.
Go to the Setup menu.
Click on the Accounts icon in the Get connected section.
In the setup form, you just need to give your email address and password, the handset will be looking for the relevant settings for you. When your account has been added to your handset, a new page asks you for a few options, like the push preferences.