The main strategy is have Deuterion, Hydrogedon, Oxygedon and Water Dragon Cluster into hand or graveyard, Bonding - DHO set and activate it on oponent Battle Phase to summon Water Dragon Cluster, activate Water Dragon Cluster ability to sacrifice it and summon both Water Dragon in Defense Position in the End Phase so you can change them both to Attack Position in your Main Phase.
How to play:
Use the Skill to discard Deuterion / Hydrogedon and search for Oxygedon or discard Oxygedon and search for Deuterion / Hydrogedon.
Use the ability of Deuterion to search for Bonding - DHO.
In case you are missing one of the pieces, you can use Foolish Burial to send one of the monster to the Graveyard or using your own Galaxy Cyclone to destroy your set Bonding - DHO and remove it from the Graveyard to search for the Water Dragon Cluster.