I have just started learning and practicing and went out shooting for practice in a local concert at a small bar.

Most of my photos have turned out terrible and most of them similar have similar issues as the picture below.. So please take a look and give me some advice on what are the things I have done wrong and how to improve them for next time.

Also my equipments are: Camera: Nikon D-610, Lens: 35mm f/1.8

ISO: 4000, f:1.8

And here is the image: https://i.sstatic.net/0s5MG.jpg