how can i fix my heater matrix in a golf 1.8 gti mk11?

hi i have already taken out the broken one just dont know or unsure on how to put it back together and the haynes manual is pants it shows nothing i have parts all over and not sure where they go if u could help it would be much apreciated thank you it is for a golf mk11 1.8 gti the year is 1989-1990.