How to reset windshield wiper timing?

Hello,
In order to put them both in the correct sequence. First remove the arm that came off before. Shut the switch to the off position. The install the arm parallel to the second wiper arm. This will keep them in sequence.

Also keep in mind that if the spline on the arm or the shaft is worn the wiper will go out of sync again. So inspect and make sure the component in good condition. If not replacement of the arm or the shaft would be necessary.

Here is a helpful video:

https://youtu.be/4YhpeoZoKu8

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.