A proof using induction always has two parts. Naturally, it starts with a statement about all integers, i.e. it has the form $\forall n\in\mathbb N: P(n)$
- In the first part, you must prove that the statement is true for the integer $1$. In other words, you must prove $P(1)$.
- In the second part, you can assume that the statement is true for $n$ (where $n$ is general), and from that, you must prove that the statement is true for $n+1$. In other words, you must prove $P(n)\implies P(n+1)$.
I don't know exactly where you are stuck, so please, in the comment, answer these questions:
- Did you write down what the statement looks like for $n=1$? If so, what does it look like?
- Did you already prove the statement for $n=1$?
- Did you write down what the statement looks like for $n+1$? If so, what does it look like?
After you answer these, I can help you further.