How to show dynamic data in a popup using shopify app?

[sniper2804]

Hi,

I am new to Shopify app creation process. I want to create an app which has the capability to display a pop on a merchant's store. The pop up needs to show text which the user had entered in the app in admin dashboard. 

I have searched all over the internet but was not able to find anything which will help me do this simple functionality.

Till now-
1. I have created an app by following the official tutorial of shopify using nodeJS starter template.
2. I have gone through the theme app extensions which I think might be the solution, but can't find a way to dynamically display text.

Is there someone who can help me with this? What am I missing here? This seems to be a trivial thing that many other apps have implemented.

Thanks in advance.