Things are changing and arbitrage trading is not as it is before. I only succeed in arbitrage on one trading and many opportunities I see with it always end up with either wallet maintenance or I cannot withdraw. I lose money on this in 2018 and I will advise you that if you did not have any good software for this then avoid it.
to perform arbitrage, usually people monitor the list of sell and buy requests on the exchange. then comparing with other exchanges, if the difference is large and the number of orders can generate profits, it will be executed immediately. arbitrage for me the price reading speed and execution.