To start up applications automatically at login, you could add them to your ~/.xinitrc
or so. Here is an example.
gtk-redshift & calised & urxvtd -q -o -f &
To have them opened on a specific tags / screen, see the awful rules : https://awesome.naquadah.org/wiki/FAQ#How_to_start_clients_on_specific_tags_and_others_as_floating.3F, specifically this example :
-- Set Xterm to multiple tags on screen 1 { rule = { class = "XTerm" }, callback = function(c) c:tags() end},