No, you didn't miss a note. You should have a note which includes the names of the chemicals.
Example:
Let's say that
Sulphur is
#1,
Acetone is
#2,
Chlorine is
#3. (Only example)
Now, if the note says
first button from the top (left to right) is
#2, you aren't going to press it first.
If the note says
second button from the top (left to right) is
#1, you are going to press it first, then
first button from the top (left to right)
But, the problem is, the machine has mixed the buttons. There should be help in the same note.
So, in-game:
#2--#1--#()
O----O----O
#()--#()--#()
-O----O----O
You press #1 first, then #2. Get it now? Note says the correct order of the chemicals. (That order is actually correct, which i listed up there.)
Here's the full correct order.
I'm not 100% sure is this correct. You test it.