Help setting a source as one of my shortcuts

[CDFeighery]

I just purchased a new Samsung AU7175 4K LED (2021) TV.

And I'm trying desperately to set the four shortcut options, you know the button on the top right corner of the remote. What I want to do is program each of the four options, right, left, up and down. My wish is to set my PS4, Chromecast on each their buttons (for instance left and right). I hold the button in and reach what appears to be the shortcut menu, and I know want to assign a source to one of the shortcuts, I can clearly see the huge plus button down under channels, but how the heck do you go about assigning a specific source to a shortcut? I thought I figured out how to do this, but never get any further than a message appearing telling me "not available". Please help me figure this out.

I'm totally crazy about my new tv! And so excited! But this issues is really putting a damper on what otherwise has been a satisfactory experience with your product.

I look forward to hearing from you soon.

[AndrewL]

@CDFeighery: When you press and hold the top right button on the Smart Remote to access the Shortcuts menu, your available sources will be visible at the top of the screen. They can't be added via the '+' button, as this is reserved for channels, but it is still a handy way to switch sources quickly. Alternatively, tap the Home button > Source > Navigate to the relevant source > Tap the Up directional arrow > Add To Home for ease of access.