The only thing they havent explained properly, is the forest and why they are in it and if there are surrounding villages and such (whats been happening before hand). Chapter 0 gives the impression villages are being attacked ? . 2nd chapter hinted the MC and his old master were looking for something but hadrdly found anything. Other than that, we know that theres something dangerous in the forest, all the martial arts guys gathered in the area and supposidly putting their differences aside to work together. Unfortunately MC and the old man didnt hear what they were saying cause he was scolding the MCs rash actions and they missed the meeting.
So yes, doesnt make sense why they started in the forest and events leading up to it, but everything else does. Its only chapter 3 too.
i agree the disciple coming up behind him should of made more noise. he didnt look like in a state to be sneaking.