docs: Add user guide for *Send someone a private message*

templates/zerver/help/index.md

@@ -72,7 +72,7 @@ as an **organization**.
 ## People
 * [Check whether someone is here or away](/help/check-whether-someone-is-here-or-away)
 * [Invite a friend to Zulip](/help/invite-a-friend-to-zulip)
-* Send someone a private message
+* [Send someone a private message](/help/send-someone-a-private-message)
 * [Send a group of people a private message](/help/send-a-group-of-people-a-private-message)
 
 ## Streams & Topics

templates/zerver/help/send-someone-a-private-message.md

@@ -0,0 +1,39 @@
+# Send someone a private message
+
+Instead of composing a new private message through the compose box,
+you can compose a private message to someone using the user list.
+
+1. In the user list on the right sidebar, hover over the name of the user
+you want to privately message to reveal a down chevron (<i
+class="icon-vector-chevron-down"></i>) icon to the right of the user's name.
+
+    !!! tip ""
+        You can search for a specific user by entering the user's name in
+        the **Search users** input.
+
+2. Click on the {!down-chevron.md!} Select the **Compose a message to
+(user's name)** option from the actions dropdown.  This will open the
+compose box with the target user as the recipient.
+
+3. Type your message.
+
+4. Once you have completed your message, you can now send your message
+to the specified user by pressing the Enter key or clicking the **Send**
+button, depending on your settings.
+
+## View your private message history with a user and compose
+
+If you'd like to look at your message history with a user while you
+compose your message, do the following:
+
+1. In the user list on the right sidebar, click on the name of the user
+you want to privately message.
+
+    !!! tip ""
+        You can search for a specific user by entering the user's name in
+        the **Search users** input.
+
+2. Upon clicking on the user's name, your view will be narrowed to your
+private message history with the selected user, and the compose box will be
+transformed to include the selected user's email address in the
+**one or more people...** field.