Follow the red "bike" signs out of town, paralleling the train for a while. The paved road becomes dirt very quickly and passes in and out of the ski zone a few times. The scenery is just incredible in all directions.
As you get higher, you pass through working pastures with the Eiger, Mönch, and Jungfrau looming thousands of feet above. Those cows don't know how good they have it!
Near the top, follow the train again for a bit until you get to Kleine Scheidegg - a good place for a break, food, and drink.
The trail is occasionally forested, but is mostly exposed and quite hot while climbing. Thankfully most of the hills, though steep, are on nice tacky dirt and are very rideable.