Making your app play nicely with Lowser is very simple.
1. The main script file should be called "index.lua". Place it, with all its resources in a folder with the application's name (spaces and everything is allowed; make the name nice: "Foobar's Magical Quest", not "foobar_game")
2. Instruct your downloaders to install your game in memorystick:/PSP/GAME/luaplayer/Applications/ . Of course, they also need Lowser in the Applications folder, and they need the Lowser-specific script.lua in the luaplayer folder, but these are bundled with the official LuaPlayer release.
3. Make your game *exitable*, please. Just make sure that the end of the file is reachable. (Your main loop could look something like this:

while not Controls.read():start() do
	[ your app's code ]
end)


There's some nifty things you can do, too. If your app leaves a coroutine running, it will keep running after your app has "quitted". (background music player, anyone?) Just make sure to keep a pointer to youur coroutine in the global scope, so that you can fetch it and kill it from your own app.