dueling network is still confusing because i don't know how to use xyz or synchro or theme decks
i only play burn decks
xyz you just have to place 2 or more cards on top of each other & then place the xyz card. To do it on Dueling network you must hover over a card then click overlay & click on another card of the same level, then you click on your extra deck & pick an xyz card with the same level as the other cards as long as the criteria on the card is matched. After you picked the card select overlay on that & click the 2 cards on top of each other
synchro you need to get 2 or more cards (if not specified as anything else on the card) whose total levels equal up to the card you want to synchro for, you must tribute them just like a normal tribute. One of the cards has to be a tuner, which is on the card so you can tell. Any card can be used in a synchro unless the synchro card says otherwise.
That is my in depth explanation of the 2