What is CMB2?
CMB2 is a developer's toolkit for building metaboxes, custom fields, and forms for WordPress. WP Darko uses it in various plugins for creating user-friendly setting/edit screens.
How do I install it?
When one of our plugins needs this toolkit to work, a message will be prompted telling you to install and activate it (CMB2). Everything is automatic and all you have to do is click Begin installing plugin.