To display a dock in Pop!_OS, you will need to install a GNOME extension.
Installing the Dash to Dock Extension
Navigate to the Dash to Dock extension. Click the slider on the right which says “OFF”.
Click the “Install” button which pops up, as seen below:
You should have now installed Dash to Dock.
Tweaking Dash to Dock Settings
To adjust settings, first refresh the installation page. You should now see a settings icon, like this:
Click that to bring up the settings panel, as seen below:
You can tweak settings within this panel to your liking.
Ubuntu Like Dock
On that settings page, adjust some of the settings to make it look more like Ubuntu 17.10 if that is the theme you are going for. Here are some settings which work well: