Try going to options, Preferences, and under startup settings "Load last project on startup. Under projects "Load template project... Hit Alt-enter, and under audio settings at the bottom is the command for saving as default... ps on the bottom left of the Reaper preferences window you can search terms related to your problem, without having to read all the preference settings, just in case you don't know. I didn't know the location of the settings above so I searched the word "last" for example.