The most important question you should ask is what problem you are looking to solve when hiring this support agent.
Normally, most support agents handle technical support tickets, phones and live chats. Will this be the first support agent I hire? This means that the process of deciding who to hire varies significantly to know if they have resources (other support agents) to support them or if you want this person to help define the processes.
Support can make or break your business, so it is imperative to make sure you hire the right person or people. They represent your company in many ways and keep your customers happy when they come to you for help.
If you can provide some additional goals that you have in mind for what you want to accomplish, I would be more than happy to give you more information.