Then just outline it as directed. You clearly realize that you can't put in a lot of detail, so I don't see why you worry about this. They don't want to know the brand of pH meter, type of HPLC column, components of growth medium, etc. that you might foresee necessary. If some small part of it changes, fine. I don't think it will be a major problem. You are not committing to a grant description here. Just an outline. Don't worry about equipment, either. That's what research funds are for.