To say the time (on the hour) in Chinese, you simply say the number like you would in English, and instead of o' clock, you say "dian" third tone.
Example 7 o'clock is "七点” qi dian.
To ask what time it is, use the character for asking how many of something ---- you might remember it from asking someone's age. Instead of Ni ji sui? (How old are you?), you say Ji dian?
Or if you want to emphasize the what time is it right now add the "right now" (xian zai) characters in front, making the complete sentence "Xian zai ji dian?"
This is on the lingt site if you'd like to practice.
We made clocks today and practiced telling time in Chinese to the hour and half hour. We read a book called "Old Wolf", which uses many different times throughout, and each child had to move their clock hands to the appropriate time, hold them up, and say aloud in Chinese the correct phrase in response to the time we just read. Most seem to have it down, so you can practice with them at home.