Ehm... you are showing exactly how this is done with your screenshot - I am confused :)
In your screenshot, you define that the current query returns at most 10 results, regardless of how many results there are.
Maybe the confusion is about this remark:
rfernandez How do I implement this (fixed result limit) in my own form?
You would usually never need a fixed result limit on a form query, because a form only ever loads one record per relation. Fixed result limits make sense for lists, sub queries, aggregation, etc. - but not when defining a data form.
