Creating new extensions and then configuring to work with blueface

I have PBX up and running now but am trying to configure my spa941 linksys phone to see the extensions I am setting up in PBX. So far I have two extensions set up in PBX but neither of them are working when I enter in the sip details into the voip linksys phone and would really appreciate some direction from any experts out there. Thanks in advance.