The default setting for your Day Sheet screen is to be sorted by Vehicle 2 (Delivery Vehicle).

At any time you can change the sorting of your Day Sheet screen.

Your Day Sheet screen can be sorted by Origin, Destination, Product, and either the Pickup or Delivery Vehicle.

To sort by any of these, just click on the column heading on the Day Sheet screen.

You can play around and see the effect this has on your Day Sheet screen, note it will always return back to your default when you next login to MyTrucking.

Your Default Day Sheet Screen sorting can be changed between Vehicle 1 or 2,  or by Destination. This is done by going to Account - General Settings and changing the Opening Screen.
The option "Day Sheet ( by Vehicle 2)" is the default setting and means the Day Sheet will be sorted by the Delivery Vehicle:

Once you have selected the main sorting field (Origin, Destination, Vehicle, etc) the jobs within each section are then sorted by Time.
By default, the Pickup Time is used, but if you have Delivery Time enabled you can also sort by that.

Have a read of the article linked here for more information on ordering jobs on the Day Sheet.