Why the tray is the whole adoption plan at first
For a cat who has never used a litter tray indoors, toileting is the skill the whole homecoming hinges on. Outdoors she chose soft earth, in a quiet spot, with room to dig and cover; a plastic box with scented crystals in a busy utility room matches none of that, so early misses are information, not defiance. If she reliably uses a tray within her first small territory, expanding her world is simple. If the habit never forms, every room becomes a possible toilet and frustration builds on both sides. Treat tray training as the first fortnight's main job and let everything else wait.
Start small: one room, one tray, no choices to get wrong
Confine her to a single easy-clean room with the tray in a quiet corner, as far from her food and bed as the room allows. A small territory does two things: it keeps her close enough to the tray that using it is the path of least resistance, and it lets you spot patterns quickly. Put her gently in the tray after meals, naps, and play sessions, when cats naturally need to go, and let her step out freely if she wants. When she uses it, keep the praise calm and offer a small food reward nearby rather than a fuss over the tray itself.
Choose litter she would recognise from outdoors
This is the detail that decides most cases. An outdoor cat knows loose soil and sand, so a fine-grained, unscented, clumping litter poured reasonably deep feels familiar under her paws; strongly perfumed litter, coarse pellets, and covered trays with flaps all ask her to accept several novelties at once. Some adopters place a little clean soil or a piece of turf on top of the litter for the first days as a bridge, mixing more litter and less soil as she uses it. Keep the tray clean — scoop promptly — because a cat who buried waste outdoors expects a fresh spot each time.
When she chooses somewhere else, read the message
If she toilets on a rug, in a plant pot, or in one repeated corner, she is telling you what she prefers: softer material, a quieter position, a spot away from household traffic. Move a second tray to where she actually goes rather than battling over where you wanted it, and clean soiled areas thoroughly with an enzymatic cleaner so the smell does not invite a return visit. Never punish misses or rub her nose in them; for a cat with no indoor toilet history, punishment only teaches her to hide where she goes, which makes the problem harder to see and solve.
Expand her territory only as the habit earns it
Once she is using the tray reliably in her room for several days running, open one more room at a time, adding a tray in the new area so she never faces a long trip back. Some cats graduate in a week; others need the small room for longer, and that patience now is cheaper than re-teaching later. Divide the work openly at home — who scoops, who checks for misses, who logs a clean day — so nothing depends on one person's memory. Those litter-training chores and progress notes can live as assigned duties in KinsLe's Care Teams, where completed tasks are marked with a timestamp and the whole household sees the habit building.