Freelander 2001 TD4 ES

Hello all - I'm a newbie to this site and hoping that somebody can help with some advice.
A couple of days ago the glass on my driver's side door mirror was broken. The casing and the backing plate are all in tact it's just the glass that has cracked. I've bought some replacement glass off Ebay and it came with a backing plate (convex and heated)
My question is how do I go about replacing the glass? Can I use the existing backing plate and if so how do I remove this in order to fit the new glass? Any help would be greatly appreciated.

pull the existing one towards you, is should pop out, look at the back of the new one to get an idea how it clips in.

re your mirror glass , pull the old backing base of and just clip your replacement on .