its easy as heck and worth it. I don't care about looks so I like to be able to fit more like 2 or 3 stacked buisness cards under the barrel. That way no matter how hot it is or how wet and no matter the shooting position its not going to touch.
Its real simple here is what you do.
remove action from stock.
carefully mask off the stock all around the top.
Get a socket about hte same size as the barrel or slightly larger. Wrap sand paper around it. sand the channel out useing long even strokes. Frequently put the barreled action back in the stock and check barrel clearance with buisness cards.
finish off with progressively finer sand paper till its as smooth as you want it.
clean it well with compressed air and or damp cloth.
apply some stain on the wood. follow directions probably has to dry overnight.
If you really want to go all out do a hand rubbed true-oil finish. you can buy a kit for 20 bucks comes with instructions. Takes like a week you keep applying layers every day its mostly waiting for it to dry.
If you want to go fast use minwax whipe on poly from home depot. You can do a few coats in a day so you can do the whole thing in 1 day and get to shooting.Doesn't look as good as true oil but its the barrel channel who cares.
Not every rifle is designed to be floating barrel make sure yours isn't supposed to have a pressure point before you get to sanding. The action may wiggle more after sanding the barrel out if it does you might want to glass bed it.
If you are going to bed it you might aswell do it now while its all masked off etc.
here is one I bedded and floated. This one I stained and used whipe on poly. Never shot it before I did the work on it but its sure a serious tack driver now! This was my second bedding job and 3rd time doing the barrel channel. My cz 527 i just did the barrel channel haven't bedded yet.