WordPress Social Network plugin BuddyPress provide all the necessary features for a social Network site. One of the important feature is member registration which allow a visitor to registor on site using a form and get a profile, access to sitewide activity stream, open groups and other open content. To enrich your social network site experience you can include BuddyPress free plugins like BuddyPress lock for Private community, Member reviews, group reviews and a lot of Premium BuddyPress addons
After installing and activating BuddyPress, We have to activate BuddyPress registration page, for this we have to go to BuddyPress setting – Pages.
Hiding DashBoard for Non Admin Users
BuddyPress Member Registration
Firstly we have to allow anyone can register from site setting.

Under General Setting you will find the option to mark tick Any one can register on WordPress site.
Save the setting and go to BuddyPress Pages setting.
Registration page is ready, now anyone can register from this page.

You can also create your own BuddyPress Registration form Using Gravity Forms
When a New Member Register on site, Admin can approve the account from Users – Manage signup
Hiding DashBoard for Non Admin Users
Use free WordPress plugin “Remove Dashboard Access”

You can setup Dashboard user access to admin, editors and authors and disable for subscribers and other member type.
Setup the redirect page for non admins like for BuddyPress users setup to Member profile page, they can update the details. No need to access the dashboard. Checkout the video below.
If you are just starting to create BuddyPress powered social network checkout Free BuddyPress Theme BuddyX as the theme comes with one click child theme and demo setup.