There are 2 screws on the front side. Undo them and gently pull the fairing off. Then you can install whatever windshield you got to replace that. I got a Cee Bailey's windshield. Cee Baileys | Honda CTX 700 2013-Up Windshield
If you go to the "CTX700forum.com" site there is a very detailed how-to on this subject, with pictures.
The difference in the site......CTX700forum......without a dash between 700 and forum.
Hope that makes sense.
That site has much more info on the bike and is a lot more active than this site.