This tutorial will go over how to reindex products on your site. If you are making any major product changes, or changes involving taxonomy vocabularies you will need to reindex your site.
Reindexing your site is super simple, but depending on the amount of products you have it can take a while. You can still do anything on the site that you usually would, as long as this is open in a new tab so it can keep running until it's at 100%.
To reindex the site: