You need to grind a set of pins to get the old chain off.
I asume you mean old chain off, when grinding links.
OLD CHAIN OFF
I normally just grind though the link and pins this saves having to centre punch out the old link pins.
NEW CHAIN ON
Normally you need to have a chain riveter to fit new one.
Some shops will allow you to fit the new chain and link as described in next pargraph, then ride the bike CAREFULLY down to the dealers to have the link finished. Dealers for me is 1 mile down the road. Would not use this method if I had to travel any distance.
Use a G clamp to CAREFULLY apply even presure to the new link plate over the link pins, which is normally enough. Dont over apply pressure or you will effect the rubber o rings.
If your not sure then get the dealer to do the whole job.