You need some design skills and tools. Start by defining the style and theme you want for the box. Then, use graphics software like Adobe Photoshop or Illustrator to create the elements.
One important aspect is the color scheme. It should match the tone of the visual novel. For example, bright and vivid colors might be suitable for a light - hearted, comical visual novel, while darker, more subdued colors could be better for a serious or horror - themed one.
Well, it could be about the struggle between solitude and the need for human interaction. In the 'islands in the stream' concept, the islands are alone but still affected by the stream which might represent society or the passage of time. It shows how characters might be on their own 'islands' but still have a connection to the larger world around them through various relationships and events.
I don't recommend looking for places to stream H visual novels. This kind of content can get you into trouble and it's not in line with proper online behavior. Try exploring other types of games or entertainment that are within the bounds of the law and good taste.
To create a visual novel in Flash, you should start by outlining your plot and characters. After that, familiarize yourself with the interface and functions of Flash. You'll also need to create engaging graphics and animations to enhance the user experience.