Phrases
1) On time = punctual, not late, happens at the time that was planned
     The conference was well-organised. Everything began and finished on time
      The 11.45 train left on time (= it left at 11.45)
2) In time for something/to do something = soon enough (near the time or deadline)
3) Too late = opposite of in time (it is past (exceed) the deadline)
4) at the end = at a time (when in a range of a month, for example) when something ends. (At the end of the month, at the end of the film, at the end of the course). (Not *in the end of January.)
5) at the beginning = opposite of the at the end (time when something is in an early of a range of time, ex. at the beginning of the day)
6) in the end = to say what final result of a situation was:
     We had a lot of problems with our car. We sold it in the end (= finally we sold it)
7) At first = to say what is the result before main event happened
     At first we didn't get on very well, but in the end we became friends.