War, I don't know where the ancestors' graves are, and there are no relics. What should we do in this situation in traditional customs?

In ancient times, clothes were used as graves. If you really want to do traditional customs, you can ask a geomancer. They'll find a way. This situation depends on local customs. Our custom here is to rebuild the cemetery. Since I can't find it, I will build a new cemetery.

If possible, you can build a small pavilion, and bamboo forest is better.