How do i get a dowloaded app to start with windows in tray or taskbar

Hi assuming you are specifically referring to UWP apps downloaded from the Store, this does not seem so obvious. Methods that work with traditional 'desktop programs' (not downloaded from the Store) don't seem to work.

For example, to launch Groove minimised to the taskbar, you can use free Autohotkey, and this very crude script:

run, explorer.exe shell:AppsFolder\Microsoft.ZuneMusic_8wekyb3d8bbwe!Microsoft.ZuneMusic
Sleep 3000
WinMinimize,,Groove Music,

in a file with extension ahk

Create a shortcut to that and place it in the Start-up folder (easily accessed if using Open Shell start menu) otherwise
- for user
C:\Users\<userid>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup
or - for all users
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp

I do not even know where downloaded apps are stored on my laptop

By contrast with traditional downloaded programs- which you can still use of course- you're not limited to Store Apps for most Win 10 editions- Google is great at questions like this:


Most users should have no need to access that protected folder.

Tasks scheduler - launch minimised: I found this thread for you:
Start Batch File Minimized via Task Scheduler