Need to manually approve new users

I need to be able to manually approve all new users before they are granted access to the website. Right now when a new user registers, they automatically get access to the website. I am using the WP Profile Builder Pro application, which I like because I can customize it, but I need a way to be able to check that all new users are authorized to have access to the information on our website before granting them access.

I have tried to use the WP Members http://wordpress.org/extend/plugins/wp-members/ and the New User Approve http://wordpress.org/extend/plugins/new-user-approve/ plugins, but neither or these seemed to work with WP Profile Builder Pro.

Profile Builder Pro recommended that I add a custom usermeta with meta_key “pending” and meta_value “yes” or “no”. However, I am new to wordpress and I am not sure how to go about doing this. Can someone please direct me to a good resource for this?

I would really appreciate any help or advice that anyone had on how to resolve this issue.

Thanks