Manually increasing or decreasing importance or relevance of relationships

I am a teacher creating a game. The students will be trying to solve a crime fiction case. I am working with text from subtitles of 150 video clips. I want to show connections between different videos based on the words and phrases within each video. 

1. How do I now form connections and relationships between words and phrases within and between different videos?

2. Is there a way to manually increase or decrease the importance of certain relationships? I plan to add student comments into the knowledge graph and link their key words and phrases to relevant videos. I want to be able to make it visible which students have provided more relevant insights. 

3. Is there a way to embed the videos within the text so that it is easy to watch the video and see the knowledge graph at the same time? 

I am looking forward to your response.

Thank You

Dustin