You can add contacts by clicking on "Contacts" or the address book icon on mobile devices and searching for their username. Tapping their username will create a new Wickr Conversation and add them to your Contacts list.
To make a group conversation, you must use the notepad/pen icon (iOS) or pen icon (Android). After you have added your desired Contacts to the new Conversation, press "Create" to start the new conversation/group and add the username(s) to your Contacts list.
Android: 1:1 conversation
Android: Group conversation
iOS: 1:1 conversation
iOS: Group conversation
On desktop clients, you will use either the hamburger "Menu->Contacts" or the address book icon at the bottom left to create a 1:1 Conversation.
Group Conversation: Click the + sign in the "Conversations" tab, enter their username in the search field, and hit "Enter" to search. If Wickr finds the Contact, you can then click on the Contact and click "Create" to start a new 1:1 Conversation. Or you can search for more Contacts to add to your group conversation.
You can remove contacts on mobile or desktop clients by clicking/tapping their profile icon, and selecting the "Block" option.
To create a conversation, see: How do I start a Conversation
IMPORTANT: Please do not try to add Wickr IDs by tapping the "+Invite Contacts" button. This is only to invite contacts to Wickr through your email or text applications individually if they are not in Wickr, yet. For more information, see: How can I invite my friends to Wickr Me?
Using Wickr's Contact Finder option is another method to add your current phone contacts who may already be in Wickr. See more at: What is Contact Finder?