Silo Entrance

Shortcut
there is a tunnel between the two pits in this area. Using the route gets you past a lot of patrols. climb the stairs by the first pit. Flip over the railings and then drop down. slide along them until you can drop onto the crate by the tunnel entrance.

First mission
It's helpful to use a FOX Operative here. Take the shortcut to the second pit. Take the ramp out and you will be in the general area. Use the map to find the goal.

Finding Snake
take the shortcut, however this time in the tunnel is a male Officer. if you use one yourself it's pretty easy to interrogate him.

Weapon Location
Opposite the entrance tunnel (where the battle with null starts) is a ladder. it goes to a walkway with an RPG-7 on it. Watch out there is an RPG armed guard there.

Boss: Null
hide behind a container, He will use three bursts of his gun before needing to reload. Shoot him while he reloads. don't let him use his machete as this will cause massive damage.