My crochet patt shape armholes how do i do it?

patt says sl st across 2ch sps &into the next dc, 2ch 1dc in next 3ch sp, patt to last 3ch sps, 3ch,1dcin next 3ch sp how would i do it when it says patt to last 3ch do i repeat from beginning or do i just sl st in to the next 3 ch