I have a website that currently doesn't have every page created that is affiliated with every link. That means "Link 1" may work, but "Link 2" might not. Therefore, I would like to create a custom 404 page. I have tried making a ".htaccess" file, and putting it on the root of my server, but it just doesn't work. What content should I put into the .htaccess? And, where should I put it?