1995 Chevy S-10 Ventilation problems... only defrost works

The ventilation settings haven't been working properly for the last few months. At first it would work some days and others not?! Now it wont work at all as the air comes out only from the defrost vents no matter what the setting is. My husband is not a mechanic but he is willing to give it a try if some kind person would give me a hint as to what we should try to do first in order to hopefully fix this problem. I have read through Googgle researches that it might be a leak from a vacuum hose... but we are still looking for those vacuum hoses? What do they look like? We have started to dismantled the front dash decorative pannel but haven't seen anything yet. Should we remove the whole dash itself? Please anyone help us... we unfortunately can't afford to have it repaired by a mechanic!! Thank you so much in advance for any hints...