It takes a standard cable release. The socket is located on the left side of the body, near the bottom. To take long exposures on the ETRS requires moving the A/T (Auto/Time) switch, which is located on the lens, to T.
First the camera is wound to cock the shutter. The A/T switch lock screw is backed out until it stops, then the switch is moved. Once triggered (at any shutter speed setting on the body), the shutter will stay open until the switch is moved back to A.

The Speed Grip is a good way to attach a flash, and will take a hot shoe type flash without needing a cable. Any kind of flash bracket that fits will work, if used with a cable to the PC flash socket on the camera.