Macbook: how to initiate a backup now using Time Machine

System Preferences - > Time Machine
Then select Disk to backup
Then right click on the icon of that disk with a clock logo --> Back Up Now

Erase process has failed : cannot erase a disk using disk utility on Mac

One potential solution:
try unmounting the disk. There might be problems affecting this disk / programs currently using this disk.

How to see an outline of your word thesis article --- using document map

On mac,
View - > Sidebar -> navigation
thumbnail is also a good function