Reset the mechanism and enter the first part of the combination | Chapter 4: A Friend in Need Thief Guide

The correct first combination is 319

Approach the safe and examine its side walls, thanks to which you will find an interactive button on the left and on the right. Press any of the buttons and run quickly to the other one. Completing this puzzle will allow you to enter the first p[art of the combination> If you want to, you can follow the game's suggestion and take a look at the document that you obtained earlier (Great Safe Combination), which contains a hint concerning the first part of the combination. You need to enter the first digits on the note, i.e. 3, 1 and 9. The attempt to enter the second part of the combination, results in a cutscene featuring the Thief-Taker General, who will, unfortunately, manage to stop Garrett. Get prepared, because you will have to act quickly, after the cutscene ends.