Storing a folding stool without blocking a passage
A compact folded shape helps only if the stool can be opened fully on a suitable surface.

Decide whether it is a seat or a step
Not every folding stool is designed to stand on. Read the product's intended use and load limits rather than judging by its height or solid appearance. If you need access to a high shelf, choose a suitable step product and follow its instructions; a folding seat is not a substitute.
For sitting, compare seat height with the activity. A low stool may be convenient for a short task but awkward to rise from. For stepping, consider whether the product provides the required height without reaching beyond its safe use. Do not place it on another object to gain more height.
Measure it open
The unfolded footprint can be much wider than the seat. Make sure all feet can rest on the surface specified by the maker and that the stool can lock fully into position. A narrow gap between furniture is not suitable if it prevents complete opening.
Keep fingers away from folding joints and follow the opening sequence. Check for damage or a mechanism that fails to lock. Do not use a faulty stool while holding it together with a strap or other improvised fix.
Give it a clear storage place
A folded stool behind a door can interfere with the door's movement or fall when the door opens. A narrow wall gap may be better if the stool remains stable and accessible. Measure the folded depth, including any latch or handle that protrudes.
Avoid storing it where retrieving it requires climbing or moving a heavy stack. The purpose is to make a task easier, so its own storage should not create another awkward task first. Keep the area clear enough to carry it to the place of use.
If hanging storage is offered by the product, use a suitable mounting method and load-rated support. Do not suspend it from a small adhesive hook merely because it is light when empty.
Before buying, read the instructions or ask the seller for them. A clear explanation of intended use, locking and storage is more valuable than a photograph showing the stool performing several unrelated jobs. Choose the item for one defined need, then use it within that design.