Diy Replace shower tray?!

[Moomoola]

Hello, I thought I’d siliconed a leak on our shower..but it seems not and now it’s damp and rotten around the plaster board and some of the wood it’s resting on. How difficult is it to take it out and mend it ourselves? We can’t find a plumber and probably can’t afford the one we do find.
all advice welcome!

Are the walls tiled in the shower enclosure? How good are you at tiling, and do you have any spares of the tiles in that area?

Ideally you need to remove at least the bottom row of tiles so you can tile down onto the edge of the new shower tray after it's installed tight to the wall.

Hello, thank you! Yes, I tiled the kitchen. These are small mosaic tiles in sheets, and we have few spare. I’ve been you tubing and it seems I need to widen a hole caused by drips below and clear out some of the rotten base boards and ssupporting wood, not joists, I hope.
then I guess I may need to cut into the walls from outside at the base and see where the leak actually is.
then cut out a few rows of tiles, unscrew the screen and remove it and the tray..and see what’s underneath! Does that sound right? It’s a ceramic base and it would be nice not to have to buy a new one.
Thanks so much for your response.
just can’t afford a plumber atm. We have just had a few unexpected bills. Ulp.