The legal connecting time is 45 minutes.
If your scheduled arrival is 06h30, then the first flight you can take is at 07h15 or later. I would allow for 1h20 minutes to be comfortable.
For changing terminals you have 2 options:
Upon entering the terminal, you must pass passport control ... after that, look for the bus symbols and the word "correspondances" which means "transfers" or "connections" in French. The transfer bus will take you around from 2C to 2A to 2B to 2D
to 2F, in that direction.
You can exit the terminal completely and walk from 2C to 2F. Out of 2C, follow signs first towards 2E. Then in the middle of 2E, there is a connection on the lower level between 2E which will bring you direclty to 2F. This may even be faster than the bus.
ADVISED, your aircraft from Singapore can arrive at any terminal. It could arrive at an actual terminal or it could arrive on a hard stand, upon which you will be bussed to the terminal.