Free version
In your WordPress dashboard, go to Plugins > Add new
In the search bar, type Modern Fields.
As it’s relatively new, you may scroll a little before to find it.
You can also download it directly from here: https://wordpress.org/plugins/modern-fields/
Click on install then activate.
Modern Fields is installed!
You should see a new Modern Field entry at the bottom of the main menu.
Pro version
First, install the free version.
Then, download the plugin directly from your account.
In your WordPress dashboard, go to Plugins > Add new > Upload plugin.
Activate the plugin.
Go to Modern Fields > Licence to activate your licence and unlock all the features.