Initially I used to have control over which post comes on top, or bottom or how frequently a post pops up but after the recent introduction of the algorithm for the For You Page, it's no longer that way. You need to strive to put your posts in front of viewers. Let.me give you a little hint about the algorithm. There are scores that influence the frequency of your posts in the for you page. For example activity count counts, then individual post engagements increase the score also. If you do this you'll realize your posts frequently popping up in the for you feed