You should apply to anywhere between 7-15 law schools. These should be a mix of reach, target, and safety schools, with at least two schools in each category:
Reach schools are schools where, well, it’s a reach for you to get in, but you have a chance.
Target schools are schools where you’re a fit with expectations for LSAT scores and other relevant scores, and thus have a pretty good chance of getting in.
Safety schools are schools where you exceed benchmarks for relevant scores and where it’s extremely likely you’ll get in.
Of course, the number of law schools you apply to will depend on your financial resources for applying, as well as your goals.