"What is a term-to-term rule?"

It's an instruction that tells you how to get from one term to the next, for example, in the sequence 2, 5, 8, 11, 14, … The difference is clearly +3 each time; therefore, the 'term-to-term rule' is..

“Add 3 to the previous term.”

"Let's see how this works step-by-step!"