1. Under Setup, go to Global Actions.
2. Create a new action with matters as the target object.
3. While creating this global action, you will be able to choose which fields are on the layout.  Be aware that only the first five fields will be shown in the side pane.
4. Once the new global action has been created, go to Publisher Layouts.
5. Select the layout and add the new action to the Mobile & Lightning Actions section of the layout.

You can now create a matter from the side panel by selecting the plus sign (+) at the top left-hand corner of the pane. 

When you log an email, you will notice a toggle button at the top.  When enabled, you will be shown the logging options first when you select an email.  You can disable this functionality the same way you enabled it.

If the email you want to relate to a record has attachments, you can choose which ones you want to include or not.  After selecting the blue Log Email button, you will see the Include attachments section at the very bottom.  Click on the drop-down arrow to see a list of all the attached files.

To relate an event or email to a matter, you must select (click on) the event or email. Then select the blue Log Email (or Event) button.  Select the drop-down menu in the lookup field and select matters.

You can create time by adding the multi timer to the email pane.

1. Go to Setup and type Outlook or Gmail into the quick find box.
2. Select Outlook or Gmail Integration and Sync.
3. Go to the Email Application Panes section and use the drop-down menu to edit the pane of your choice.
4. On the left-hand side of the page, you will use the component palette to drag-n-drop the multi timer component onto the pane layout.
5. Be sure to select Save, and you're done!