Please note. If you are sharing the account, updating the default format will effect all users who login with the same user name.

Set your selected formats including per page and sort by.

My screenshot includes arrows that simply point to selections/changes I made in the Format Drop down.

Once you are satisfied, click the blue Save button.

Do not make changes in the Name Your Search field. You will overwrite the My Default Format.
Click Save.

Done.

Next time you login your choices will be selected by default.