How do I install RetroDECK on the Steam Deck?

Quickstart guide

Put the Steam Deck into Desktop Mode Steam button > Power > Switch to Desktop
Install RetroDECK from Discover
Start RetroDECK first time in Desktop Mode
Choose where RetroDECK should create the roms folders Internal or SDCard.
Put the BIOS inside ~/retrodeck/bios/ for more information read: Emulators: BIOS and Firmware
Put the ROMS inside ~/retrodeck/roms/ or <sdcard>/retrodeck/roms/ depending on your choice
In Steam desktop go to the tab Games press Add non Steam game to My library and select RetroDECK to add it into your library. If that is not working you can Right Click on the RetroDECK desktop icon and press Add to Steam in the menu.
Optional way: Get RetroDECK Steam Grid art and add it to your Steam library with BoilR. Or add the art manually from SteamgridDB for the Steam Grid.
Switch over to game mode and go to RetroDECK on the Steam Grid under Library > Non-Steam
Add the Official Layout under Controller Settings -> Controller Layouts -> Templates in the Steam Deck called RetroDECK: Official Layout with a version number and apply
Launch RetroDECK and enjoy

Read up on the Controllers: Steam Deck to ease your navigation.
Read up on the EmulationStation DE: User Guide
Check out our other software recommendations Steam Deck: Software recommendations.
Check various optional optimizations that can make some emulators run even better Steam Deck: Optimizations.

Put the Steam Deck into Desktop Mode Steam button > Power > Switch to Desktop

Open the Discover application.
NOTE: Depending on what language you have set in Desktop mode your Discover application can be named differently.
Inside Discover search for RetroDECK and press the install button.
After the installation is finished, launch RetroDECK from Discover or in the program menu under Games > RetroDECK.
Follow the first time setup instructions and choose where RetroDECK should create the roms folders Internal or SDCard.
Open Steam while still in desktop mode.
Inside Steam go to the tab Games press Add non Steam game to My library and select RetroDECK to add it into your library.
After this is done you can now see RetroDECK in Steam Deck's gamemode after you return to it from desktop mode.

Go back into gamemode by pressing the return to gamemode icon on the desktop.
Go to RetroDECK on the Steam Grid under Library > Non-Steam
Press the Controller Icon
Go into Controller Layouts and press Templates
Add the layout for RetroDECK called RetroDECK: Official Layout with a version number.
You can now use RetroDECK and it's ready to populate with ROMS.
If you are unsure on how to add ROMS and BIOS to RetroDECK follow the Getting Started Guide from Step 2 and onward on how to add them.

Get RetroDECK Steam Grid art with BoilR or add it manually from SteamgridDB for the Steam Grid.
Check various optional optimizations that can make some emulators run even better Steam Deck: Optimizations.
Read up on the Controllers: Steam Deck to ease your navigation.
Read up on the EmulationStation DE: User Guide
Check out our other software recommendations Steam Deck: Software recommendations.

Put the Steam Deck into Desktop Mode Steam button > Power > Switch to Desktop
Open the Discover application.
Click on the updates tab.
If there are any updates available it will be shown here.
Click on the Update or Update all buttons.

If you have Decky installed and the AutoFlatpaks plugin. You can update RetroDECK from gamemode.
Read more here: Steam Deck: Software recommendations