Once, you have installed and activated Everest Forms Pro and entered the license key, you can activate the available add-ons on your plan.
Navigate to Everest Forms->Add ons Page. All the available addons will be listed on this page. If any add-ons are not available in your plan, upgrade the plan.
You can see the Install Addon button below each addon section. Click on the button and the addon will be installed.
If you don’t see Install Addon or find any addon missing, click Refresh Add-ons button.

Now you will see the Activate button. Click on the Activate button and the addon is installed. You can repeat the same for any other addon.

You can also install the addons manually. For this, you can manually download the addons zip file from your wpeverest account page. Once you download the zip file, go to Plugins->Add New ->Upload Plugin and upload the zip file. Once uploaded, install, and activate it.