Could someone tell me please, how do I attract tadpoles, I need 2 Froglets for my quest and have no idea where to start. Thank you

You have to start with spawn, dropped by a land frog.

You get one land frog for every complete set of tadpole, froglet and underwater frog (including any ghostly frogs) you have spotted in other gardens.  Deduct any land frogs you've already had spotted, and that will tell you whether you are due any land frogs or not.

The first land frog spotted in your garden drops spawn, if you have an empty (cleared) table, and after that it's every multiple of five.   As you've already had one spotted you'd need to get to your fifth, so you need to have at least another four complete sets - if you don't have those, you'd need to spot more in other gardens.

Then leave out high berries for the frogs, and an empty plate for the spawn, and your fifth spotted would drop the spawn.  You'd then need to go underwater and let the spawn attract tadpoles.

Once you've attracted tadpoles, you can leave out a low table of wild berries for the froglets.  You get one froglet for each tadpole you attracted (and after that, you'd get one underwater frog for each froglet attracted).

Thank you, think I may abandon quest, it seems quite complicated