You can use a combination of Buttons and Actions to achieve simple Topic navigation
Scenario: Leaner finishes Content Topic 1, clicks a button on the last screen & move to Content Topic 2
1. Open Content Topic 1 and in the Editor select the last screen in the topic (in this example Screen 2)
2. Select the Assets tab in the left-hand task bar then drag & drop a Button asset into the screen 
3. Click on the button and select Actions from the Button Properties taskbar on the right-hand side of the Editor
4. Add a 'Link to screen' action to the button and select Content Topic 2
5. Save the change
Result: When the Learner reaches the last screen on Content Topic 1 they can click on the Next button and be directed to Content Topic 2