How I select double conversion IF frequency ?

How I select double conversion IF frequency ?

or recomand double conversion design tool.

plz help me.

There are a lot considerations about the IF selection, like
the image rejection, the power consumption, the VCO design..
You can fist read some IEEE paper on transceiver design to get some feeling on their choices

For chousing the first IF in a receiver the main consideration is to be high enough to make easier filtering the image frequency.
The second IF should be low to allow using a high gain and stable amplifier.

The usual rule of thumb for high performance receivers is to make the first IF at 3x the highest frequency the receiver will tune to. The second IF is a standard value that has a wide selection of commercially produced filters.