To Play use the w,a,s,d keys to move mouse to aim and click to shoot. What you need to know (not really there is not anything to force you): the variables on the bottom right corner is the ammo and max ammo from left to right when your ammo runs out (there is no ammo counter because you have a melee weapon) you will reload which is not that bad. the variable on the top right is your HP when it reaches 0 your ded son.
How your knife works: You have a knife it weights 0 kilograms and you can swing every second and the damage (how much hp an enemy loses if hit) is 100 per swing (instant kill). there are 2 ways to play in the test. the bottom half is for normal target practice and the top half is like playing against an enemy who will swing at you with the same weapon.