You don't copy them to the Enterprise version, you import them.
Go to the QMC, go to Apps. Near the bottom you will find an import button. Click on that, browse to your app and hit import.
You don't have to wait till the import of one app is done; you can immediately continue start import again and select the next app.
It currently (to my knowledge) is not possible to import multiple apps at the same time, so you have to do it 1-by-1.
The connections will be imported and you can manage them via the QMC.
If your intention is to use a SQL database instead, I suggest you change your local code to already point to a database instead of XLS. This does NOT have to be the production database you will use later.
That is one of the great things of Qlik Sense:
You can develop locally, point to a test database, import the app to the server, and on the server use the QMC to edit the connection and point it to your production database.
If you import another app and the name of the connection is 100% the same as earlier used connection name, it will use the connection already on the server.
You can easily import your desktop app to server if you are using the same excel then you have to create a Connect statement again the reason is your machine name and server machine name will be different so you have to recreate the connection path incase if u load the data your refresh will get failed .
if you have more tab in your backend you have to change all the table from statement instead of going and changing each and every tab create a variable and pass the variable after the lib statement so that you dont need to go each tab to change the from statement for the first time you have to do after that just change the variable pathitself it will work
but any way u have to create a connection string again i hope you got what u want