[This is an incomplete draft of the the tutorial in note form, to be completed.]
Use the 'start/stop' button to start logging. The next press of the same button will suspend logging and another press will continue the log in the same file. I tend to start a log at the beginning of the day and leave logging on because if I stop it during a break I often forget to restart.
To terminate the current log file and start a new one you have to use the confusingly-named 'Reset' function. To do so, first use 'start/stop' to stop logging, then hold down the 'lap' button until the reset occurs. The current log file is closed and the next time you use 'start/stop' a new log will be started. Nothing else is altered.
Menu button > Settings > Map > Lock On Road > Off
If this option isn't set the log can include a lot of erratic assumptions about which road you were on! I find that this option needs to be checked regularly - the device sometimes seems to set it to 'On' unprompted!
Accessing log files on the device connected by USB to your computer:
The logs are in:
Garmin > History
With names like this:
You can copy them to your computer and/or upload them directly to a web mapping service.
[We will add material discussing the use of mapping services and the conversion of log files to navigable routes in a future tutorial.]