During your visit to the Vanir Shrine in God of War Ragnarok, you will come across a large circular door that is currently locked. There are two braziers on either side of the door that must be lit within a very short amount of time between each other. If you have tried, you will notice that it is impossible to try and light them one at a time.
In order to make this work, you will need to chain the sigil arrows together so that when you detonate one, it will cause a chain reaction that will make the others blow up.
To light both of the braziers within the time limit, you will need to shoot a sigil arrow next to each of the braziers. You will then have to use your third arrow to bridge the gap in between them so that when you blow up the middle one, it will chain over to the other two and both of the braziers will be lit and you can progress further into the shrine.
If you are unable to get this right, check out the video guide below and it will show you how to light both of the braziers.