The Yongnuo YN560 IV Speedlite is a fully manual flash. So there is no communication whatsoever with the camera, apart from the flash signal from the camera to the flash.

I understood from your posting, that the flash does indeed flash on manual. Then that is all there really is. On manual mode and with a manual flash, you have to find your settings all by yourself or with help of a flash meter.

So set your camera to a shutter speed of equal or slower than your camera's flash sync speed (in your case 1/200, I think).

Set your aperture to what you want to achieve creative-wise. Set Iso to 100 for start. Now take an image with flash turned off.

This is your background or ambient exposure. You can now tweak it to your liking (by changing ISO or adjusting the shutter), then add flash to further illuminate the subject.

The ambient exposure can range from a completely dark frame, if you want to totally control the light, to almost correct exposure, where just a smidge of light is missing to emphasize the subject.

Turn flash on and start with a a medium setting like 1/32 - then correct the flash setting to your liking.

Voila!

As the flash is manual only, whenever the situation changes, you have to re-adjust the flash completely.

If you need a flash that does that automatically, you will need a more expensive TTL Flash, which communicates with your camera. Please be aware that each camera brand uses their own protocol for TTL, so make sure you buy the flash for your specific camera.

You set the off-camera flash tag to the question: So make sure that the trigger unit is paired with the flash before. You can test that via the test button on the trigger. The rest stays the same.