According to the show's IMDb page, it looks like the first season is slated to be 10 episodes long. This is a fairly common season length for shows today, especially on cable networks like Freeform; the era of 13- or 20-plus-episode seasons is fading fast. The first two episodes premiered back to back in a two-hour block on April 20, but going forward, episodes will air one at a time every Tuesday.
It's unclear right now whether the show will choose to do a two-hour finale or not, which will determine when the series finale airs. If the show continues at