The Tomb of General Tarsis is one of the Story Missions in Anthem. During it, you will visit the titular tomb. Inside, you will have to solve a few simple puzzles and face Dominion soldiers.
The mission starts after you visit all 4 Tombs of the Legionnaires during the mission of the same name. Go back to Fort Tarsis and meet with Faye. After that, you can go on a new expedition.
Go to the tomb marked by the game. This mini-location is called The Haven. The entrance to the tomb is hidden behind the waterfall (see the picture above).
The tomb is filled with weak scorpions. This place also has a few chests with loot - explore the area carefully.
Go to the large gate - you have to open it. Luckily, all the puzzles in the tomb are easy. Find the pedestal with two rotating objects (picture 1). Next, find the symbols on one of the walls (picture 2). Interact with symbols that aren't covered by plants.
Go inside the new room and eliminate more scorpions. The next locked gate requires you to solve three puzzles with symbols on pedestals.
A symbol is near every pedestal (e.g. the cross presented in the picture above). Place the same symbol on the left side and then start rotating the symbol on the right - keep rotating it until you find the solution. Complete all three puzzles to trigger a cut-scene during which your character will reach General Tarsis's sarcophagus.
Start with eliminating Dominion forces - they have appeared in the previous room. Use large pillars as covers. Eliminate Dominion Storm Valkyries as fast as you can.
After eliminating this group, go back to the previously visited chamber to face more enemies. Respawns are blocked here so be careful. Eliminate elite Dominion units by using your Ultimate and other abilities.
Go to the exit. You will encounter more Dominion forces, including turrets. You don't have to fight with them. You can simply run away. Don't forget to avoid getting tracked by turrets - more information on What should I do if my javelin is targeted? page.
Fly to the Strider marked by the game. Land on the machine to end the expedition. Watch the cut-scene during which you meet with Faye, Owen, and Haluk. You also get moved to Fort Tarsis automatically.