Park at the place called Plan Ronchet at the junction between the road coming from Valgrisenche and the path leading to the place called Grand’Alpe (spelt Grand’Alpe on the IGN map at 1/25000, Grand Alpage on the Italian map at 1/25000 and most probably by mistake, Gradalpe on the OSM map). Head for Valgrisenche a mountain village that you'll reach from Arvier in the Aoste valley. In Valgrisenche, take the road towards Bohne which then overlooks Beauregard Lake's left bank. Roughly 1.5 km after the end of the lake and before heading down a windy trail leading to Surier, you'll come across a junction.
(S/E) Take the path heading west. You'll reach a group of chalets at the place called Grand'Alpe.
(1) Ignore a path that heads off to the left sticking to the main track (north-west). The path gradually heads up along the left bank of Grand'Alpe Torrent (Rio Grand'Alpe on the Italian map). You'll reach some alpine chalets at the place called Revéraz-Décot (IGN map), Revera Basse (Italian map) or Revera Bassa (OSM).
(2) Go past the chalets heading north-west. Around high point 2170 the path turns into a trail through the pastures: ignore a trail heading off to the left towards the torrent instead head right reaching the torrent a bit further up.
(3) Cross the torrent (high point 2200) and head north with the torrent to your right hand side. Here, you'll be able to see Saint-Grat Lake with Ruitor Massif in the background. After about a kilometre the trail steers away from the torrent then heads up a steep slope. After a few bends, cross the glacial rock bar to reach the lake.
(4) Don't head north along the lake, instead go left, and between some blocs of rocks you'll come across a trail heading up over the lake. The trail is windy and heads east. Head up the bends sticking to the same direction until you get to the first neves and reach a berm with a cabin (Refuge Adami).
(5) Head back the same way to get down.