What are these blinds and how do they work?
This blinds are called "Venetian blinds. If the blinds are very long they have guide cords at both ends. This is the case in your situation. 

From the first picture you can see two sets of cords comming out of the frame.

The most left set of cords are used for tilting the blinds when they are down. There is a rotating mechanism inside the frame that can make the individual elements tilt in the direction required to block the sun.

The other set of cords is used to lower or pull up the complete set of elements.
If still working you can unlock the mechanism by pulling both cords to the right. Once free you can lower the elements by releasing the wires. Locking the elements at the required position works the same way as the release procedure.
It depends on the make if you have to pull the cords in the same or in the opposite direction to lock the system.