Newbie issues with permissions (admin panel vs ftp)

Hello to you all. Using Grav 1.5.6. Quark theme. Using Admin panel, LangSwitcher, Login plugins.
I am experiencing issues and I hope you guys can help me. So here it goes:

  1. Permissions issues. Using FileZilla, I can create folders and files. Permission is 103/80. If I use Admin panel, I can access (read, write) these files and folders. However, if I create a file using admin, permission is 80/80. So I cannot access the folder and files created via FileZilla. I wanted to create a file and put it in the 01.accueil folder (80/80) but got “Operation not permitted”. I can however move, the file to another folder (03.sections 103/80).
    I tried to modify permission to set folder to 775 and files 664 but got a denied message for folders and files created via Admin pane.
    How can I fix this?