iMessage on Mac

[iMore Question]

I am trying to set up iMessage, and I have signed in with my apple ID which also shows my cell phone number when I go to preferences....accounts. What I want to know, is why doesn't iMessage know my contacts that are in my cell phone. I don't want to have to go and add every person that has an iPhone. I know that this is possible because my gf has a mac (same as mine) and the same iPhone as me, and she can just type in a person's name and they pop up and she can message (text) them from her laptop, and she didn't have to add any contacts. HELP! Thanks!

 

[kch50428]

Set up your mac to sync contacts to iCloud.. System Preferences>> Internet/Wireless>> iCloud