What is your printer? Try putting in nothing more than G28 in your start script. You will then have to set the temperatures from the web interface. Note that when you change the process the profile will change to "modified" and in order to save it you must click update profile or save as new. My start script is specific to my machine/process. Also you can write gcode commands for moving, priming, and wiping the nozzle as well as setting the center of the build plate. Look at what G92 does.