Once you have decided to start the business the first step is to buy a domain name to be the face of your business. Once you have that, you should setup emails to use your domain instead of a free one like gmail. Its very easy and free.
2. Sign up
3. Go to where you bought your domain name. (I suggest name.com)
4. Edit your DNS records to match the values provided by Google.
5. Wait a few hours for your changes to propagate.
6. Login to google apps with the user you created in step 1.
7. You should now be able to use Google apps to send and receive emails.
8. (Optional) You should setup some common email aliases. (Conatct@yourbusiness.com, firstname.lastname@example.org, you should also setup a catchall email address so you get all the emails.)