I guess you do an Internet search. I did just that and found these:
https://www.youtube.com/watch?v=O1aIGp1Z-FY
https://www.youtube.com/watch?v=uMXiAHHBl68
https://www.youtube.com/watch?v=dVdmd2X6Lxs
and
https://www.youtube.com/watch?v=Y-eAvoBI59Y
and
https://www.youtube.com/watch?v=yAg2s3sSZBU
Having done it, it's one pig of a job and there's no guarantee you won't be repairing something else on the machine pretty soon. I would consider seriously simply getting a new machine, say from John Lewis, with a 5 year warranty (Don't bother with an aftermarket extended warranty)
Anon
March 2016