first time buyer

You don't need a buyers broker. You NEED a real estate attorney. A good real estate attorney, who is experienced in NYC closings will review your contract, review the building financials, handle the title search (if you want), and represent you at the closing. Your real estate attorney can negotiate your offer as well.

Personally, I found having a broker to be very helpful. I have lived in NYC for 30 years and didn't think I needed a broker. I knew what I wanted, knew the neighborhoods, etc. But having a broker who knew the requirements of every co-op board like the back of her hand saved me a ton of time (and heartache). Having someone who could represent me as a serious buyer and not just a looker got me appointments in buildings that didn't allow open houses, etc.

Is the seller using a broker?

#3 asks a really good question. Be very careful. You really don't want to screw this up.

You want your real estate broker to represent you. You are not paying to your broker as a buyer. Why not have the professional make the process easier for you. You should ask a friend for a good real estate broker.

Good attorney - mandatory. Buy-side broker - optional.