This template is view-only, so I can’t add or place the controls here. Fork it into your workspace, then share/open the editable copy; I’ll add an EC11 encoder and two medium PCB pushbuttons with clip-on caps along the USB-port edge, with the EC11 nearest the GPIO header.
Please also provide the preferred button cap size—or I can default to 12×12 mm tactile switches with removable caps.