If it's the kind that requires the wrench with two pins I just use a pair of channel locks to unscrew that large round nut.

Find two nails, bolts, drill bits any thing that fits the hole on your blade nut, these must be a tight fit. Now use a a suitable lever between the two and unscrew it.

You need a mans touch.

buy a new grinder and this time don't loose the tools that come with your electric powered tools.

on your angle grinder the central locking nut has two holes in it ..around the head of the grinder ..they vary with different machines is a button ...this locks the head of the grinder ...then you need the special flat tool that fits into the two holes and removes the nut ...you can sometimes undo it with stilsens ..but not often ..a hammer and chisel will remove it but the nut will be ruined...take it to a hire shop and they will remove it for you ..may cost just a smile!

Borrow some spanners. Most people have an angle grinder these days.
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Looks as though we have a nutter giving thumbs down. Just goes to show their lack of intelligence. Bet they didn't even answer the question.