I would like to build a RF with FSK modulation but I do not know how to start.I know basic electronics but I have no idea how to combine that knowledge.Thanks

 

Is there a particular reason or goal to use FSK? Is there a specific data rate, or distance involved?
Frequency or power limitations? It would take more than one textbook to cover all "RF and FSK" terms used together.

If you are just starting out.......there are two ways to go. First is the old fashion method/way.....analog circuits. You will need to study and build STABLE sine wave oscillators. You will need at least two....one audio and one rf.

And the second way is the new method......digital clocks and filters. Here the oscillators are replaced with STABLE digital clocks.....and filters to convert square waves into sine waves. This is cool for the micro controller and computer crowd.

So.....it depends on what tickles your fancy.

 

If you want to do it without a microcontroller, look into the NE567 tone decoder for some ideas.
www.experimentalistsanonymous.com/diy/Datasheets/NE567.pdf

Or using a similar technique with tone generation and detection chips:
http://www.vfx.hu/proj/fskmodem/fskmodem_eng.html

If you are interested in doing it from the ground up with a microcontroller you might take some cues from this simple project which uses FSK to transmit a symbol to a receiver.
http://www.cappels.org/dproj/LCRFLINK/LCRFLINK.htm

 

Nice job thanks DickCappels I been looking at something like this .