From Tignes Val Claret, follow the track along the Lanches chairlift.
At around 2650m there is a track on the right, which you should take to reach the start of the Vanoise chairlift.
A hundred or so metres further on, you can either head due E up a slope towards the start of the cable car, or take the gently sloping path due N that runs along the bottom of a rocky shoulder. This saves time and elevation gain.
Alternatively, you can take the funicular up to 3020m and then follow the Champagny ski lift.

Once you reach the Champagny ski lift, you climb along the pistes (if the resort is open), which are supposed to be less crevassed because they are groomed/maintained. In fact, there are quite a few crevasses lurking around even if you're in a ski area.

On foot

Go up to the cable car arrival point and take the rock bastion, which is then equipped with a rope.

Alternatively, you can climb up the long snow shoulder/ramp that starts a hundred metres before the arrival of the cable car and leads to the ridge leading to the summit, at about the level of the letterbox(!).

From the letterbox, climb up the steep slope to an antecima defended by a 30/35° slope, depending on the conditions.
The summit, which fluctuates, is about fifty metres further up on a ridge of snow that is more or less tapered and often gnarled.

On skis

Up to the top of the chairlift, the slope is not very steep (ski rating 2.2) and glacier safety equipment is not necessary if you stay in the marked area. The rest is much more interesting and wild.
From the summit of the Grande Motte chairlift (3409 m), climb the NE face, which becomes steeper and steeper and is often gnarled at the summit. You can join the E ridge, which leads easily to the summit. Slope 35°, crampons and ice axes useful depending on conditions. At around 3450m you cross the rimaye, be careful. Descend by the same route or by the NE ridge and NE face.

Remarques

The rocky bastion above the top station of the cable car is sometimes quite uninviting and a fall from it would be dangerous.
In short, it depends on the conditions, but the snow ramp and ice axe provide good belaying if the snow is hard.
All tastes are catered for, but it is generally preferable to go on days when the resort is closed.
Equipment.
On the glacier, in foggy weather, there is a risk of unexpectedly leaving the marked areas and finding crevasses.

The summit is very often blown over with an accumulation of wind plates on hard snow, ice axe recommended, the fall leads to a giant toboggan just before the antecima.

The descent from the shallow E face (which then leads to the top of the slopes via the much steeper N E face) is often defended by a more or less high cornice, so beware...