Just clip it to the base of the shoulder stap.
The strap originally clipped to the hardware holding the shoulder strap. It's best to alternate, clip one side in front and on the other side it clips on the back of the shoulder strap. Clipping everything to the back means the bag wants to tip forward when you carry it.
FYI, I always was anti-handle strap, feeling you'll miss a picture if you are holding the camera bag. I do like the handle strap for lifting the bag off the shoulder and setting it down inside the car, or getting it from under the plane seat.
We went to adding a second ring for handle straps and backpack stap when we switched to using the nylon slider at the base of the shoulder strap.
Having struggled with large metal D-rings to keep the strap flat so it evenly distributed the weight. But the was frustrated with it bunching up. I experimented using the slider hardware which has a narrower slot and it worked! Who'd a thunk? It wasn't meant for this, but it kept the shoulder strap flat and this change happened around 1986.
Some folks like using the mountaineering caribiners for clipping on the handle strap or hanging a roll of gaffer tape to it, or the press passes, etc.