Time Machine does not show MyBook - is there an easy way to fix this?

I am not very tech savvy, an old girl trying to learn new tricks. As per instructions that I spent several hours searching for, I tried to erase MyBook but the utility says that it is completely full (4T) with no purgeable items. I purchased the MyBook due to several reviews that touted its ease of us – that’s not what I’m experiencing. I had hoped to plug in the power chord, connect MyBook to my MacBook Air os10.12.6 (yes, I know it’s old; I want to update it but want to back it up first, hence the purchase of an external drive), start TimeMachine, click on the MyBook icon and let it do its work. What am I missing? Is there a better external drive to purchase that intuitively works for Macs?

Hello,

Please refer to the following KBA article: Starting macOS Time Machine Backups to My Cloud and Network Attached Storage