In general try the least aggressive polish or compound to see if it works. Are you going to use an electric buffer? You probably will need to. There are some pretty good videos on the web. Search for restoring a boat hull video or compounding a boat hull.
In many cases where the oxidation is not too deep, a product like Buff Magic works.
If the oxidation is really bad, the first step is often wet sanding, followed by compounding, polishing and waxing.
It can be a lot of work