How do get the proving FREQUENCY-TIME graph by using oscilloscope?
Note that your chip isn't going to make a 12 GHz signal on its own. You need to use it with an appropriate VCO, loop filter, and reference clock generator to make a complete synthesizer. 

Having done that, you can pre-scale down your 12 GHz synth's output and use it as the REF input to a second PLL (probably optimized for fast tracking rather than low phase noise). Then use your 'scope to monitor the VCO control signal of the 2nd PLL to get the frequency-time graph you're looking for.