Park in the car park at the Col de Bavella next to the tourist information centre (remember to pick up some information). The trail is marked with red signs and wooden posts.
(S/E) The trail starts with an ascent through a forest of Laricio pines and then arrives at a flat area. Looking back, you will have a beautiful view of the Aiguilles de Bavella. Continue along the path and pass the antennas on your left. Continue until you reach a sign for "U Cumpuleddu".
(1) Turn left and follow the red markings. You will reach another intersection. Turn right towards "U Cumpuleddu". The path climbs to a flat area still in the Laricio pine forest. You will reach another sign indicating the view of the "Trou de la Bombe" (Bomb Hole).
(2) Take a short detour to the left to admire this amazing geological formation in the distance. Retrace your steps to return to the original route towards the hole. You will reach a new fork.
(3) Turn left towards "U Cumpuleddu". The path then becomes slightly more complicated. Steep passages over rocks lead to the Trou de la Bombe. Follow the red markings carefully!
(4) The more daring may venture inside the hole. The path is no longer marked at this point. Take care, as this approach requires some mountain experience: a few steps of climbing are necessary to secure your feet and hands, especially on the descents. Not recommended for those prone to vertigo.
Return by following the red markings. The path is slightly different than on the way there for about 50 metres. It avoids the large steep slab, which can be slippery when wet. Then follow the red markings and the signs for "retour Bavella" (return to Bavella).
Keep to the right, continuing to follow the red markings and the sign for "retour Bavella". When you reach the sign for
"Belvédère".
(5) Take the path on the right that climbs up a slight rocky promontory: the path is not shown on the IGN map but is marked on OSM. You will have a beautiful view of the Aiguilles de Bavella; the other large rock, called Dame Jeanne, is difficult to access.
Return to the main trail and descend carefully for about 100 metres. Cross the stream and stay on the red trail until you reach another intersection about 100 metres further on. Turn left onto the red trail and leave the trail on the right
(6). Continue straight ahead (red markings) to reach the Col de Bavella car park (S/E).

I couldn't find the final section to access the bomb hole, which is the objective of this hike, as it isn't detailed. Lots of different routes end in dead ends and I only found one spot close enough to take a photo. It would therefore seem impossible to reach it without climbing.