each size chain needs a specific size file or stone - check details with your supplier.
A lot of amateurs struggle with sharpening because they are only sharpening the cutters and forget to file down the depth guages as well.
There are a few decent instructional videos on the internet to guide you and they generally include a few other useful tips to keep your saw running well.
As has been said in a few other threads, if you can afford it, do a proper chainsaw ticket which includes maintenance of saws and the cost will be reimbursed in reduced payments for sharpening and servicing etc, not to mention the satisfaction of doing for yourself and also losing the hassle of getting to service centres or sending your chains off in the post.
Sods law also dictates that you will have problems just when you really need the saw
