Once you are in the start section, press F12 (opens the developers console).
In the developers console, go to the Network section and check the Preserve log and Disable cache.
On the WSS portal, navigate to the Service section (the Locations section in Network will be the first one shown).
On the developers console, you will see a bunch of data where you will have to find the packet out of the ones called directprovider with the following Request Payload method "getLocationsForDefaultCustomer" in the Headers tab:
Once you find it, select the Response tab and copy the content: