need help with vco

I think amplitude shift keying can be realized using voltage controlled oscillator(vco) as main component .
1 - how can I build the vco cicuit for square wave input (v ctrl) and output
at radio frequency (RF) stage.
2- If any other simple method ,using L,C,R and transistor...., to build amplitude
shift keying (ASK)
3-any help is appreciated.

thanks.

Shifting the frequency with a VCO control voltage is frequency shift keying (FSK), not ASK.