How to get continuity and handoff working

[zosokm]

I have an iphone 5 and iPad mini with retina display on io 8 and iMac 21 inch 2011 and macbook air 13 inch late 2013 model(on yosemite beta). I am able to receive my iphone calls on my iMac but not my macbook air (both are on the public beta of yosemite).Handoff worked just once between my iPad and my iphone but has never worked between my desktop and laptop (all are in the same wifi network). Handoff and continuity were the most interesting features for me since I have so many apple devices but unfortunately it seems broken at this time. When I was on iOS 8.0 , I could receive phone calls from my iPad but that seems to have gone once I updated to is 8.02