In popular desktop environment like Gnome-automounting is installed automatically. Just have to plug-in USB key to access all your data in Nautilus.
I have ARCH linux, and Gnome (without GNOME-EXTRA, without AUR). There is no problem with flash memory, but there is a problem with the Samsung Galaxy. For Antergos it works well, but not on ARCH. What do I need to do to telephone automounting automatically?
https://wiki.archlinux.org/index.php/MTP -it does not work.
I write here because it is very user-friendly forum :)