Nextcloud ONLYOFFICE integration app with cpanel

Hey people I have a Hosting reseller and I have a question about that. Initially I installed the app “ONLYOFFICE” with the work tool Softtaculous of cpanel. Now I can’t synchronize the documents and open it with the NExtcloud app. Please help me because in this link explain how to configurate the nextcloud but I dont find the file .json

Thank you.