IN our LA you apply from about October, closing date is early Dec.
But it varies from one authority to another, so please check yours. For almost all schools application is via LA not the schools themselves.
You can apply on line which is quick and easy. They send you email as confirmation.
We applied for our catchment school which is pretty near as well so that was the only one we put down (had siblings for latter DC but no worries anyway if in catchment here) but most people would suggest putting down 3 or is it 4 you can put?
I live dangerously, only put one school for DS1 at secondary last year 
(It's 5 mins away)
If you are selecting schools further away from you that you are not in catchment for, please be aware that you may not get a place at any of them nor at your nearest school (if you don't list it).
So yes, check where was the furthest that people were offered places last year (info from LA) to give you a guide. For example there is a very small (one form entry) school in this city that typically offers only to familes half a mile away. OTOH my DCs' excellent infant school has kids coming from 3 miles away.
Can I put in a word for your local schools? Ofsted is not be all and end all. Do visit them - you may be pleasantly surprised and if they are close that's a real plus IMO.
What is performing below average? If you mean satisfactory then that is often acceptable. Latest OFsted framework means "good" is much harder to get so check when the inspections were done too (ie recent "satisfactory" prob broadly simlar to 4 yrs ago "good").