How do I forward calls from the main company number to cell phone

Hi Jack, I posted an article called Routing Company Calls to a Specific User Extension: A Step-by-Step Guide. You may follow it, then once you're done, you may configure the user's call forwarding settings to route to an external phone number by following the steps at https://support.ringcentral.com/article-v2/Forwarding-calls-external-number.html?brand=RC_US&product=RingCentral_MVP&language=en_US.