If the “kit” says it’s “one size fits all” or similar wording, check the instructions that come with it on how to adjust it for things that are likely to vary.
Otherwise, you’ll probably need to take measurements or, if you’re lucky, there’ll be make and model numbers on the existing parts that you can use to get replacements or new internal parts.
If you’re really unlucky, you have a bizarre but genius-designed toilet made by a now out-of-business manufacturer who found novel and unique ways around patents and lawsuits and you’d be better off replacing the whole thing.
If the “kit” says it’s “one size fits all” or similar wording, check the instructions that come with it on how to adjust it for things that are likely to vary.
Otherwise, you’ll probably need to take measurements or, if you’re lucky, there’ll be make and model numbers on the existing parts that you can use to get replacements or new internal parts.
If you’re really unlucky, you have a bizarre but genius-designed toilet made by a now out-of-business manufacturer who found novel and unique ways around patents and lawsuits and you’d be better off replacing the whole thing.