Trains will head out of London, and they’ll make stops in Brussels and Antwerp before heading into the Netherlands. The next stops will be in Rotterdam and Schiphol Airport, with the final destination of Amsterdam Central station.
To start, it will be two trains per day in each direction, as Eurostar estimates that the journey will take you roughly four hours. Apparently the flight between London and Amsterdam is like the busiest route over in Europe, so a train alternative will certainly be a welcome addition.
As for those interested in the route, you're in luck as some brand new cars from Siemens AG—e320 trains—will be running the tracks.