The actual use of Time Machine comes into the picture when you lose your data due to any reason, or the Mac fails to boot due to system file corruption. Time Machine helps you restore any particular file or the entire Mac together with data.
a. Restore a couple of files
a) Ensure your Time Machine backup drive is connected to your Mac. Now, go to Time Machine > Enter Time Machine from the menu bar.
b) Navigate to backups using the TimeLine or Up/Down arrow button. Find and select the required file, then click Restore.
b. Restore all personal files
a) Ensure the backup drive is plugged into your Mac. Press Command + Spacebar to open Spotlight. Type Migration Assistant and open the application, then click Continue.
b) Select the From a Mac, Time Machine location, or startup disk option. Then, perform as per the instruction to restore all files from the backup drive.