Your Garmin help, please

I have the official Garmin maps installed (off the back of a lorry) and I'm planning on using planned .gpx tracks from RWGPS to re-trace other peoples rides, using turn navigation. Is there something i'm missing? This is new to me.

For each course you download you need to set the course attributes, I would suggest something like this.

By default turn guidance is off, there is no way to turn it on as a global setting. Another garmin quirk.