How do you chose where you want to set a campaign?

hey divas, i've dm'd a few one shots and other non-dnd ttrpg (like call of cthulhu) so i'm not new to being a dm, but i've never done a full campaign in 5e and i want to. i've got a handful of ideas but am struggling to figure out where to set it, like what premade towns, cities, etc. to use. any help would be super appreciated. 

I have access to some of the free books here but don't own any for myself, but if you give me the name to some to look through I'm sure I can find it somewhere. 

Thanks in advance!

First off good luck with your first full campaign. Secondly what sort of campaign are you looking to run? The tone will often dictate the setting, for instance no point us saying "the Forgotten Realms is great" if you want to do a gritty low magic setting that the FR will never fit. My favourite official setting is Eberron, and almost any game can be made to fit there, but it's also not a setting ideally suited to all types of campaign and the more steampunk elements often clash with what a lot of people want from a fantasy game. Also do your players have any opinions? Might be one of them is a huge fan of a particular game or series of books and wants to go there. One of my campaigns has been set in Forgotten Realms not because I particularly like it but because they're all new players who came from Baldurs Gate 3 so setting the campaign in the same place as that game and the recent film made them feel more at home.

Depending on what ideas you've got to start you could even get away with not choosing a setting right away. If you're starting in a small village with some things going wrong that can be dropped in almost anywhere and you don't need to decide until your players decide to move on.