Ok, I'm losing my mind. Can someone help me?

Typically I'm a very methodical thinker who would sit down and read the entire instruction manual, understand it, and move forward easily. However, I'm pregnant. All the words are blurring together and my brain is short-circuiting.

We have a 2001 Toyota Sienna. 2nd row seating is two bucket seats, I'm installing the car seat behind the driver's seat. I don't even know if the van has the latch system, I can't seem to find it. I'm trying to install a Graco Snugride without losing my mind.

Can someone explain this to me in really clear terms, like you are talking to a four year old? I keep having visions of my baby getting hurt because I screwed this up so badly...

P.S. There is no owner's manual for the van because the previous owners threw it away. *rolls eyes*