Signing a contract

So where I work they are offering a sign on bonus. (Like an extra 3,000). But you don’t get all of the money at once added to your pay check. They give you 1/4 of it the first month and the other 1/4 of it at 3 months of working there and so on. They keep asking me to sign the sign on bonus contract. I am saying no because from my understanding it’s like a contract you have to stay a year or two to get your money. But they are telling me to sign it because it’s free money and you don’t have to stay a year or two. But from my understanding that it what the contract is saying. I am it signing it because what if I don’t like it. And I have other reasons of not signing it either. But I am not convinced nor I don’t think I’ll sign it. But the person who is orientating me told the other lady that I will sign it instead but I did not say that. What would y’all do?