The order is as follows: 1) upload to the site spherical panoramas from which you plan to create a virtual tour; 2) from the list of uploaded panoramas add each panorama to the virtual tour (Add to 3D tour link); 3) open the created virtual tour, edit the panorama order, select the main panorama, set transition points (tunnels).
Nodal Ninja NN4 Tripod Head with RD16 II Rotator for Panoramas featuring For Spherical @ HDR Panoramas, Supports Up to 100mm Lenses 62mm Diameter/Nadir Footprint.