Dear, just wash your conidia in sterile tap water by shwab in Petri dish, then calculate the concentration in known volume camera of haemocytometer under microscope. Then, if nesessary, dilute resulted suspension or wash with it again next Petri dish, if concentration is less then 10 in power 5.
Suppose I pour 10 ml in Petri plate and swab. From that I pour 1 ml into hemocytometer and count the colony I get average 5, what would be the concentration.