The point is to flood the field and bring out all 7 (8) Crystal beast from your deck get rainbow dragon and end on nice board + over dragon to shuffle back in their end phase and OTK.
You have plenty of options based on match up for your end board but most of the time you will try to end on scythe + dpe + 4 counter Apollo + ultimate rainbow dragon overdrive. Also most people are playing tear, bystial, and ishizu so dweller is a nice option to end on as well.
"TopTierGamingYgo" on YouTube has shown a video with a similar build going over the main combo on how to get all 7 beasts if you need help on how to play the deck.