Replacing airbox

So let me prefix this topic. I am new to the forum and have only been riding for about a year. I was given a 78 cb 400t for free. It did not run and i gave it a new battery, gas and had the carbs cleaned and learned how to ride. Now I dont know how I survived my whole life w/o a bike. That being said I dont know much about mechanics but am trying to learn without fucking up my bike. Id like to replace the airbox with cone air filters i just got. I noticed there is a carb overflow hose that runs into the airbox. Is this something i should have my mechanic do? Id rather do it myself but could use some advice. thanks again