Hey @NeeruSaini
Could you link the sample project you're wanting to use?
Typically, these have you download the project onto your file system and then open up a .aprx file from that downloaded file, is that the workflow you've followed so far?
If this is a newer tutorial like this here: https://pro.arcgis.com/en/pro-app/latest/get-started/use-geoprocessing-tools.htm
You'll have the ability to download the data or to start a blank project and go to the Open Another Project and search like this:
It doesn't show any maps by default so you'll have to start searching to get some results flowing!
Cody
There are free tutorials here, each generally has some downloadable data, or a project package.
https://learn.arcgis.com/en/gallery/#?t=lesson&p=arcgispro