Hi Max,
There are a number of ways one can visualize what you want. Here's one way.
If your DEM is a large file you may want to extract by mask to a map extent, just to keep your file size tidy. You can create a map extent by creating a rectangular polygon feature class by right-clicking your .gdb in your catalog pane. Once it's loaded onto your Contents pane, click on it, go to edit, create, and then make the map extent. Then hit the Save icon.
Be sure to save your project after each use of your tools. It's a good practice and frees up memory. Operations with rasters like Digital Elevation Models use the most memory.
From there you can run the Contour tool first and then clip the contour line to your respective polygons.
To access these tools use the command search bar at the top center of the screen. Contour requires a Spatial Analyst subscription. Check in Project (top left), Licensing, Esri Extensions to see if you have it.
You can search any of these tools in greater detail on ArcGIS Pro help.
https://pro.arcgis.com/en/pro-app/latest/help/main/welcome-to-the-arcgis-pro-app-help.htm
