Sometimes in life—and in ACT!—it becomes a matter of "which comes first." In the recipe above we assumed that you wanted to create a new Company record and that you didn't necessarily have any existing Contact records that worked in that Company.
When you create a Company record from an existing Contact record all of the pertinent contact information automatically copies into the new Company record. This is a nice time-saver because you alleviate the need to type in boring address information into the Company record when you've already entered it into a Contact record.
You can create a Company record based on the contents of a single Contact record. Generally, you'll want to create a Company record to help you organize several contacts in your database that all work for the same Company. A good rule of thumb to follow is to create a new Company record any time you have more than one contact in your database that works for the same company.
A good starting point is to sort your Contact List by Company to see if you have multiple contacts working at the same company. At that point you can create a Lookup by a specific company to zoom in on all the contacts that work for a specific company.
Your new Company record will now appear and will contain the address information, main phone number, and website as they appeared in the Contact records.