One important thing to note when talking about the time is that the French make greater use of the 24 hour clock than we typically do. You’ll frequently encounter it in more formal situations (for instance, when making appointments) and also when clarifying whether a time is in the morning or in the evening.
In casual conversation where it’s pretty obvious whether you’re talking about day or night (for instance, when you’re talking about going for dinner at eight’o’clock) it’s more common to use the 12-hour clock.
In writing, you’ll never see times written as 5pm or 3am. It will always be written 17h30(5:30pm) or 22h (10pm).
To say the time, use il est followed by a number and then heure(s)