How to take pics like this?

I mean the guy is steady but the world around him is in motion…

i have a nikon DSLR (amateur). I just wanna know how.

I believe it has something to do with shutter speed.

Fast shutter speed and shallow depth of field.

You use a fastish shutter speed, but you pan the camera to follow the bike - this makes the background blur and increases the feeling of speed. You don't want the shutter speed TOO fast, or it makes it difficult to pan & get that b/g blur.

Edit: If you look at the EXIF data, this was shot at 1/60 sec, so most of the blur is from panning & the rider is sharp because the camera is moved with them.

You PAN with the subject…

with that, the camera was set to aperture f/14 and shutter speed 1/60…

There are many examples out there of similar things… Usually motor sport, as the subject is moving in the same general direction: