New to XD cannot scroll the view

This is pretty amazing but it seems I cannot scroll the viewport. I have multiple artboards. I zoom to say 50%. Now I only see some of them on screen. I want to keep this zoom ratio and pan around the screen so I can look at the different artboards. I can scroll up and down using the mouse but left to right - no. (Arrow keys doesn't do it).

I've searched for the answer but all I get is articles about adding scrolling to artboards - it is not what I want. (I'm nowhere near that level yet). I just want to see the artboards by doing what I can do in any graphics app - by keeping a zoom level and panning around.

Please help.

Thanks.