Initially I think the regional emergency government groups would form in designated bunkers. This is to coordinate the information of who has survived and start reforming / allocating people new jobs. Secure energy infrastructure, shut most down so that engineer and such like resources can be pooled into a couple of power stations. Same goes for hospitals, water treatment etc. Some people would be allocated to work on a few farms and some to deal with managing mass funeral pyres etc. Something like The Division with the cleansers or whatever they were called.