If you are a newbie, I would suggest that you will not get your hands dirty on this one because it can cause a real mess on your site.
I want to make it clear though that some WordPress themes already have an embedded feature in removing post dates, still most themes doesn't have that. With that, you will have to hack your theme's files and remove some code. I won't be teaching you that for now, instead, I would advice you to use WP Post Date Remover plugin.
All you have to do is to install and activate, and that's it.
Removing the dates from your post is very helpful if you want to maintain the "timelessness" essence of your posts. Some bloggers however don't mind having a date simply because their blog is a sort of "diary" to for them.
So again, if you want to remove it just install WP Post Date Remover plugin and then activate.