Sure thing, alliewad95!
The question is asking where H CANNOT go, which means the four wrong answers will also be places that H CAN go. So we start by asking ourselves what we know about H .
We know H cannot go first, because only F or G go first. That would be too easy, and "first" is not an answer choice.
What else do we know about it?
H is before J, with exactly one variable between them. And J is before O. We can connect those ideas to get this sequence:
[H _ J]
This sequence, with at least three things after H (whatever is in the blank space, J, and O) means that H cannot go 8th, 7th, or 6th. Is any of those an answer choice? Yes, answer E is "sixth"! That's our winner! There is no need to test or even think about the other answer choices, because we know with absolute certainty that H cannot be sixth.
This could also have been determined in the original diagram by including "not laws" for all the places that H, J, O, K, and L cannot go, but that's an awful lot of not laws, and so might not be worth the time and effort involved in writing them all down. Instead, just use the sequences to identify these kinds of restrictions.
Adam M. Tyson
PowerScore LSAT, GRE, ACT and SAT Instructor
Follow me on Twitter at https://twitter.com/LSATadam