How to set up My Book 1TB with Time Machine on my iMac?

WD External Drives External Drives for Mac
1

How do I set up my WD My Book 1 TB external drive to serve as back up disk with Time Machine on my iMac?

I haven’t been able to figure this out and my computer hasn’t been backed up for ten days!  Please help.

J.

2

enter system preferences-time machine and under select disk choose the WD my book, then you can choose what you want to backup,i left mine at defsult. Thats it.