Available seeds

[Dale V]

I'm rather new to using torrents. On the main screen there is a column for seeds and one for peers. Two sets of numbers appear, with one set in parentheses and one set outside of them (I don't know the terminology used for either of these sets). It is evident that the seeds and peers available to me for downloading are the ones indicated outside of the parentheses. With most of my queued torrents, numbers only appear in parentheses, so these seeds/peers are not available to me and nothing downloads. My question: what moves these seeds/peers outside of the parentheses thereby making them available? Are there settings or anything I can do to actively control this?