Can someone please tell me how can i die on tutorial level for the death category.

You have to pick up enough speed and height that you fly out of the "respawn" box below the map. Ideally this is done by getting a lot of speed on the slope and then using the jump pad to fly off into the distance and die. Alternatively you can use the grenade launcher to achieve a similar effect.

Just look at the runs that are already posted, they all show several ways of doing it.

if you are bad at picking up momentum like me, then get the grenade launcher and go to the part were you have to slide down. once you are there slide down the red floor while shooting grenades right behind you. once you hit the bounce pad, use W+D while looking towards the area with the 4 enemies and the weapons, pushing you to the right. if you have enough momentum then you will go past the respawn box. if this fails, try again a few times