The "Straight Forward" Clue:
A straight forward clue is a clue that clearly states what the answer is.
All you have to do when you see this type of clue is mark down what it is telling you. The clue is clearly stating that Thumper was unearthed in Scotland, so you put an O where these two meet on the grid.
The "Greater Than/Less Than" Clue:
A greater than/less than clue tell you that something (height, salary, time, etc) is greater than or lesser than another thing.
This clue is telling you that Peanut lived before the animal in Norway, and that Peanut and the animal that lived in Norway are not a match. What you can mark down from this is that Peanut cannot have been the last one that lived because they lived before the animal in Norway. You also mark down that the animal from Norway cannot be the first one that lived because they lived after Peanut and put an X where Norway and Peanut meet.
The "Many Variables" Clue:
A many variables clue is a clue that tells you that all the variables listed cannot be a match.
This type of clue is telling you that none of these cannot be a match. Mark an X on the grid where each of them meet with each other.
The "One or the Other" Clue:
A one or the other clue tells you that one thing is either this or that.
The only thing that you can get from this clue right now is that snuffles is not the animal who is 9.3ft tall, so you put an X on the grid where they meet. You will have to come back to this clue later on when you know that either Snuggles or the animal who is 9.3 ft tall is a match with a different age.