Fridge freezer. my fridge freezer has been leaking and I had to defrost it repeatedly, once a

Question

my fridge freezer has been leaking and I had to defrost it repeatedly, once a week. it had ice clogged up at the bottom of the freezer. I have now undone 2 pannels from inside the freezer and indeed it is some ice there at the bottom, but there is no drainage whole, as far as I can see. where is this drainage tube that I should unblock? what do I need to do?