Changes

From Annecy in France, leave by train for Bern in Switzerland. Travel time by train is about 4:30 hours, and it's best to leave early. Make sure you get a connection with as few stops/transfers as possible, the best seems to be a train that leaves 7:41 in the morning. Alternatively, you can also take the bus (FlixBus) into Geneva, and take the train from there.

Anyways, with or without stop, on to Bern. If you get there early in the day, a one night stay may be sufficient (you got more stuff coming up). The Hotel Baren is a nice and reasonable option, that has everything in walking distance including the train station. Make sure you visit the Bear Cage, the Einstein house and the botanic garden (there is a restaurant up there with a nice view over the town, good option for a lunch), and find a nice restaurant downtown for a dinner.

After your time in Bern, your next stop is in Mürren, Switzerland. Take the train to Interlaken, and change trains to Lauterbrunnen. This trip takes about 2 hours. When you arrive in Lauterbrunnen, walk across the street to the Cable Car station (you'll see it when you arrive there), walk up the stairs and board the next car. The Cable Car will take you to Grütschalp (about 20 minutes). When you arrive at the top, board the small BLM mountain railway which will be waiting. The ride to Mürren will be another 20 minutes or so, and you'll arrive in the "basement" of the station. Walk up stairs to reach street level.