Do you really mean 10 GHz? What's the application?

The obvious ways to do it involve prescaling (i.e., dividing) or mixing (which corresponds to a translation in frequency) the input signal down to some lower frequency, and counting the lower frequency with ordinary digital logic. But at 10 GHz, they are not straightforward.

If you are just trying to detect whether an active 10 GHz transmitter is nearby, then there's no reason to try to count the frequency.

It would be easier just to measure the power within a band that roughly contains your signal, and compare that against some threshold. Depending on the power, that could be as simple as a tuned circuit going in to a diode detector. But it's unlikely that you'd get anything working without experience building microwave circuits.