Hi Yael - before fully launching into bottom dwellers I would suggest firstly doing at least one round of just tadpoles so that you can get spawn laid underwater as needed.  To start you need to have some spawn laid on land by attracting land frogs - your fifth land frog will drop spawn so you need another 3 land frogs attracted to your garden.  You need to check that you have spotted in other gardens at least 5 each of tadpoles, froglets and adult uw frogs to attract the land frogs you need.  Berries on a high table are all you need to attract land frogs - just remember it is like fairytales where the type of berries you choose will determine the type of spawn laid. When your spawn is laid go uw - tadpoles will be attracted to the spawn. 

Above is link then for the forum guide to bottom dwellers once you have sorted out your frog breeding :)

thanks, am reading it all, i think i am just brain froze on it xxx