Is there some kind of demo website where i can get access to the source code and deploy code for practice?

Hello,

I’m new to programming and have only done a few introductory courses in HTML, Javascript, and SQL.

I’m working as an intern in a BI department where my task is to set up server-side tracking on a practice page on our website. Before doing this, i would like to get some experience setting up Google Tag Manager etc. and seeing this data end in Analytics.

Do such demo sites exist, and how can I get access to the code, and would it be possible to deploy and see the results in eg. Analytics?

Much appreciated,
Mort