Start OsmAnd to see something like this:

Tap the 'three lines' menu icon at the bottom left to see this menu:

Ā Tap 'Plugins' to see a list of plugins. Tap 'Trip recording' to see a screen like this:

Tap 'SETTINGS' to see...

I'll be honest, I don't know what effect your selection has here. Having experimented a bit, the settings seem to apply regardless of which option you choose. I always choose the cycling icon, and have the same icon selected on the main OsmAnd screen.
You will then see the trip recording settings...

It's worth going through them all. For the time being, though, swipe down to the bottom of the list to see the online tracking settings...

Tap 'Online tracking' to tick the checkbox (as shown above). You will automatically start logging your position to the web site any time you are tracking your route and you have mobile data switched on.
Tap online tracking web address to see a screen that allows you to specify how OsmAnd should talk to our web site. Enter the address exactly as you see it here...

... except that you should put your web site user name (the id you log in with) instead of xxx and the tracking password you set in your profile (more about that here) instead of yyy. The password is case sensitive so make sure you enter upper and lower case characters exactly as you entered them in your profile. Note that the address does not contain any spaces or newlines.
Finally, tap online tracking interval to see:

We suggest you select a 5 minute tracking interval, as shown.