diff --git a/web/sidebar/community-creation/community-creation-members-modal.css b/web/sidebar/community-creation/community-creation-members-modal.css
--- a/web/sidebar/community-creation/community-creation-members-modal.css
+++ b/web/sidebar/community-creation/community-creation-members-modal.css
@@ -2,5 +2,5 @@
   display: flex;
   flex-direction: column;
   overflow: hidden;
-  margin: 16px;
+  height: 60vh;
 }
diff --git a/web/sidebar/community-creation/community-creation-members-modal.react.js b/web/sidebar/community-creation/community-creation-members-modal.react.js
--- a/web/sidebar/community-creation/community-creation-members-modal.react.js
+++ b/web/sidebar/community-creation/community-creation-members-modal.react.js
@@ -2,38 +2,111 @@
 
 import * as React from 'react';
 
+import {
+  changeThreadSettingsActionTypes,
+  useChangeThreadSettings,
+} from 'lib/actions/thread-actions.js';
+import { useModalContext } from 'lib/components/modal-provider.react.js';
+import { useDispatchActionPromise } from 'lib/utils/redux-promise-utils.js';
+
 import CommunityCreationKeyserverLabel from './community-creation-keyserver-label.react.js';
 import css from './community-creation-members-modal.css';
+import Button from '../../components/button.react.js';
 import Search from '../../components/search.react.js';
 import Modal from '../../modals/modal.react.js';
 import { AddMembersList } from '../../modals/threads/members/add-members-modal.react.js';
+import {
+  useAddUsersListContext,
+  AddUsersListProvider,
+} from '../../settings/relationship/add-users-list-provider.react.js';
+
+const subheader = <CommunityCreationKeyserverLabel />;
 
 type Props = {
   +threadID: string,
   +onClose: () => void,
 };
-function CommunityCreationMembersModal(props: Props): React.Node {
+function CommunityCreationMembersModalContent(props: Props): React.Node {
   const { threadID, onClose } = props;
+
+  const { pendingUsersToAdd } = useAddUsersListContext();
+
   const [searchText, setSearchText] = React.useState('');
 
+  const dispatchActionPromise = useDispatchActionPromise();
+  const callChangeThreadSettings = useChangeThreadSettings();
+
+  const addUsers = React.useCallback(() => {
+    void dispatchActionPromise(
+      changeThreadSettingsActionTypes,
+      callChangeThreadSettings({
+        threadID,
+        changes: { newMemberIDs: Array.from(pendingUsersToAdd.keys()) },
+      }),
+    );
+    onClose();
+  }, [
+    callChangeThreadSettings,
+    dispatchActionPromise,
+    onClose,
+    pendingUsersToAdd,
+    threadID,
+  ]);
+
+  const primaryButton = React.useMemo(
+    () => (
+      <Button
+        disabled={!pendingUsersToAdd.size}
+        variant="filled"
+        onClick={addUsers}
+      >
+        Add selected members
+      </Button>
+    ),
+    [addUsers, pendingUsersToAdd.size],
+  );
+
   return (
     <Modal
       name="Add members to the community"
       subtitle="You may also add members later"
       onClose={onClose}
       size="large"
+      subheader={subheader}
+      primaryButton={primaryButton}
     >
-      <CommunityCreationKeyserverLabel />
       <div className={css.container}>
-        <Search
-          onChangeText={setSearchText}
-          searchText={searchText}
-          placeholder="Search members"
-        />
+        <div>
+          <Search
+            onChangeText={setSearchText}
+            searchText={searchText}
+            placeholder="Search members"
+          />
+        </div>
         <AddMembersList searchText={searchText} threadID={threadID} />
       </div>
     </Modal>
   );
 }
 
+function CommunityCreationMembersModal(props: Props): React.Node {
+  const { threadID } = props;
+
+  const { popModal } = useModalContext();
+
+  const communityCreationMembersModal = React.useMemo(
+    () => (
+      <AddUsersListProvider>
+        <CommunityCreationMembersModalContent
+          threadID={threadID}
+          onClose={popModal}
+        />
+      </AddUsersListProvider>
+    ),
+    [popModal, threadID],
+  );
+
+  return communityCreationMembersModal;
+}
+
 export default CommunityCreationMembersModal;