Former means “the first of two things” and latter means “the second of two things,” however people tend to use them a bit more loosely:
Alice, Bob, and Grace are joining us for dinner. The former (Alice) is coming early and the latter two (Bob and Grace) are coming later.
Also, former has a second meaning, “earlier or past” while latter has no such related meaning; one would use later for that case, not latter:
Aaron’s former job did not pay as well as his current job.
Of his two previous jobs, the later/*latter one was more fulfilling.
You cannot use latter in the sentence above unless both jobs were listed in the previous sentence, since latter means “the second item listed”; latter does not mean later.