How do you put items together in inventory on xbox? Cant combine crystal shards 

You need to turn off auto sort for you inventory in order to combine shards into scrolls. Once its turned off you just highlight the item, hold the confirmation button and just move said item into the combine configuration, once set up in the configuration an icon will appear on one of the items in the configuration that you must hit the confirm button on and it combines them. Confirm button is PS4: X Xbox: A

What if that doesn't work?