I need help creating a hud

Hi y was doing a proyect for school and i cant manage to make a hud the only thing i want to do is a hud where when u click play it shows the amount of coins you have and a model y have the model but i cant manage to do the codes.

I want to do something like a small coin up in the left and when u kill a enemy u get a random amount of coins between 1 and 4 and it updates constanly on the hud.Like if you kill a enemy and you have 0 coins it will give you between 1 and 4 coins and that will be seen on the screen