I got the TailBlazer from Kisan Technologies. https://www.kisantech.com/index.php?cat_id=3
It's a little more expensive than other options, but it's totally "plug and play" with no rewiring required. If you can change the bulb in your taillight then you have the skills needed to use the TailBlazer.
They also sell a "plug and play" headlight modulator, called the PathBlazer, which I also have on my bike. https://www.kisantech.com/index.php?cat_id=2
Again, the PathBlazer is a little more expensive than other options, but with the PathBlazer absolutely no rewiring will be needed.