The bottom end of the shoulder straps are looped thru the small round opening on the bottom of the frame and then re-attached to the shoulder strap. IE pass the free end thru the hole and the web loop then back re-attach the free end to the shoulder strap.
If there is no way to open the top end of the straps for the top attachment point you have a choice to make. split the sewn loop and add your own ladder buckle or loop the top strap like the bottom one onto the frame. the straps for both top and bottom attach to the frame only not the pack.