Need advice building "Search" feature


I am getting close to completing my site but I have a major feature that I still need to develop: some kind of search feature.

Important: I’ve never developed a search engine feature before.

Basically, my site is a big marketplace like amazon or ebay with lots of categories and lots of products. It is designed using PHP/MySQL.

I was hoping this will search through product titles (VCHAR(55)) as well as product description (MEDIUMTEXT), which are in a “Products” table, and possibly a few other columns later on. I also have a separate “Categories” table which I will probably integrate somehow so people can search within a dropdown list of relevant categories.

Please give me a basic guide on how to make a proper and efficient search feature for my site.

Thanks a lot.