Similar process to bicycle chain.
This is by far the best explanation of fitting a new chain ( and sprockets)
I borrowed an angle grinder from the father in law for the grinding process.
The sealey chain breaker Delboy uses is the one I have, bought from Demon tweaks for £30
A few forum members use endless chains which I would have used for my last chain replacement but an open chain was sent instead, couldn't be bothered with the hassle of returning it so riveted the open one on.