Changing the 5 symbols on the top of gates level 26 so equal to 5 symbols in the left side of the sarcophagus door.
Once installed the symbols in the correct order, the symbol will disappear and hit the door to open it.
Here's an explanation for gates level 26:
Touch feathers and birds
touch the snake, then tap again feathers
Now continue to the 100 gates level 27, 28 explanation, or back to the 100 Gates Level 25 Explanation