Explanation
There are two common ways of telling the time.
Formal but easier way
Say the hours first and then the minutes.
Example: 7:45 - seven forty-five
For minutes 01 through 09, you can pronounce the '0' as oh.
Example: 11:06 - eleven (oh) six
More popular way
Say the minutes first and then the hours. Use past and the preceding hour for minutes 01 through 30. Use to and the forthcoming hour for minutes 31 through 59, but .
Example: 7.15 - fifteen minutes past seven
Example: 7.45 - fifteen minutes to eight
Another possibility of saying '15 minutes past' is: a quarter past
Another possibility of saying '15 minutes to' is: a quarter to 