Hosting landing page and web app separately?

Hello all, I'll keep it short and sweet.

I have landing page built on Wix

I have a app that was developed using a few different platforms, but heroku being the main one.

my landing page on Wix is.... "www.mydomainexample.com"

I want my web application, which is about 5 pages, to be...
"www.mydomainexample.com/page1" (page # changing with each page changed).

How do I go about doing this? Wix will not support what I need for my web application so I need to seperate them and host my web app on heroku. This will be good for the long run because my landing page won't slow down my web app and my web app won't slow down my landing page (or technically the main website where users are linked to sign up/ login/ and see the services we offer).

Your help is much needed

 

B