small fingers and a pick. Put the middle point end into the groove. Then finger pinch that into position. Use the pick to push in one side of the other end into groove and repeat for other side.
Some of these clip springs you have to start from one end, go around in sequence as you compress the other end so they will all fill into the groove. This works well too, but if it springs back, that spring clip usually goes flying, so make sure to do it inside a clear bag.