That's correct about catchment, for England.
It means a formally defined area within which DC have priority admissions. So the criteria (after the mandatory categories of SEN and LAC) would be something like: siblings in catchment, other catchment, other siblings, others. Each category would have distance as tiebreaker for when they ran out of places (unless they use lottery)
You are made an offer if you fit the entrance criteria. It is as simple as that. And you've been told that schools in your area all use distance.
So what you need to do is look at the criteria of each school you like the sound of and see how likely it is that you would get an offer. Information should be on your council website.
So if lovely school A hasn't admitted anyone over 0.7468 miles in the last decade, and you live 1.6, don't pin all your hopes on it.
Check also if any have faith places and whether you would qualify.
Use all the choices on your form idc. Conventional wisdom is to list the schools you really like in the order you like them (it's an equal preference system from the school's pov) but include on the form at least one school that is the nearest thing to guaranteed you'd get a place at (even if you don't like it much; it's better to have an iffy school that's logistically convenient, than to receive nine if your prefer necessary and be allocated an equally iffy school 30mins in the wrong direction)