In The Martian, we see the MARV for getting off Mars, which was sent months ahead of time, where is the lander they came in on and how did all the equipment (HAB, Rovers....) get there? We do not see anything around that would indicate a lander vehicle.
They used a Mars Descent Vehicle.
From there, we took the MDV (Mars descent vehicle) to the surface. The MDV is basically a big can with some light thrusters and parachutes attached. Its sole purpose is to get six humans from Mars orbit to the surface without killing any of them.
The Martian by Andy Weir
First, we descended from Hermes, and decelerated our orbital velocity so we could start falling properly. Everything was smooth until we hit the atmosphere. If you think turbulence is rough in a jetliner going 720 kph, just imagine what it’s like at 28,000 kph.
Several staged sets of chutes deployed automatically to slow our descent, then Martinez manually piloted us to the ground, using the thrusters to slow descent and control our lateral motion.
It's briefly seen as the source for the hydrazine required to make water (oddly it seems to have a number starting MAV on the side).
Supplies and construction materials were sent in advance
A total of fourteen unmanned missions deposited everything we would need for surface operations. They tried their best to land all the supply vessels in the same general area, and did a reasonably good job. Supplies aren’t nearly so fragile as humans and can hit the ground really hard. But they tend to bounce around a lot.
Naturally, they didn’t send us to Mars until they’d confirmed that all the supplies had made it to the surface and their containers weren’t breached. Start to finish, including supply missions, a Mars mission takes about three years. In fact, there were Ares 3 supplies en route to Mars while the Ares 2 crew were on their way home.
The most important piece of the advance supplies, of course, was the MAV. The Mars ascent vehicle. That was how we would get back to Hermes after surface operations were complete. The MAV was soft-landed (as opposed to the balloon bounce-fest the other supplies had). Of course, it was in constant communication with Houston, and if there had been any problems with it, we would have passed by Mars and gone home without ever landing.
In the book, the MDV seems not to have weathered the storm very well as is shown in the movie.
The MDV is on its side and there’s a breach in the hull. Looks like the storm ripped the cowling off the reserve chute (which we didn’t have to use on landing). Once the chute was exposed, it dragged the MDV all over the place, smashing it against every rock in the area