Hello, Salvador is an amazing city. Just near the terminal you can walk to the Elevador Lacerda https://en.wikipedia.org/wiki/Elevador_Lacerda
The history here is amazing At the top you are in an incredible part of Salvador, beautiful historic churches and restaurants and shops. You will have no trouble filling your day in this area.
Just be careful and do not wear expensive jewellery and gold chains and keep your phones, handbags and cameras safe.
One of my favorite cities