[consolegaming]

Well as Dismounted first suggested there's two steps to it.

changing all the id="blah" to class="blah" where blah is the id name you want to turn into a class.

But as I was trying to explain above the part defining the css also needs to be altered, otherwise the css won't take affect it'd do the same as using no css at all on that element.

and that'd have a "#" (which means class) which simply needs to be made into a "." (a fullstop) before it/in the same line it depends on the definition really. Sometimes it's as basic as #blah which would become .blah but the # and the id name will certainly be on the same line and that's all that needs to be found really.