algent A dot in front of a folder or file name means it's a hidden file or folder.
These are generally used by the system (although nothing stopping you creating your own also). Best advice is to leave them alone. For example, .config and .local between them contain all settings and preference used by your applications.
You can press Ctrl+H to show or hide them from view, or choose it from the menu - probably by unticking "Show hidden files" or something similar.
Likely, in preferences you can set a default state if you want to see them or not when you start the file manager.
An internet search for "Linux hidden files and folders" will lead to more in-depth information.
HTH