The easiest way, (since it is a google android phone)
If you dont have a gmail account you should get one! it is free and simple.
when logged on to www.gmail.com
you have "mail - contacts - calendar" and so on on the top of the page
Go to Contacts and start filling in your contacts, once that is done, simply setup your mail account on the phone to gmail and select to sync contacts!
you have a video of this here