Avatar and other info, where to find/modify

Since I find it useful when reading or responding, I would like to encourage posters to provide an avatar, national flag, location and car(s) owned. I may be dense but nowhere on the site could I find the way to update, add, or change this info. It does not seem to be very intuitive. Can anyone give me clear simple instructions.

Ok, since our mate in Switzerland is no longer with us, I’ll try to help.

Click your avatar, top right …then, when your name appears (top of list), click that and select “preferences” from the drop down menu.
On the preferences page that appears, various options are there … for more, click profile etc. on the left.