How do you store luggage on the rains

If you can carry them, you will be able to store them on the train. In the racks in the vestibule as you enter, and in spaces between back-to-back seats. Smaller bags in the overhead racks.

Are you worried about storage space, or about robbery?

Thanks was worried how I could store my 2 28inches large bags in trying to get to Rotterdam. I would have 2 carry on that I can store overhead. Do I need to go to the central train station to get the train to go. Or can I take it from the airport.

Also both getting the bags stolen and somewhere to store them.

Get it at the airport. Search timetables here: https://www.ns.nl/en
There are some trains that are more or less direct without tons of stops, and if it works out for your departure time, that should be less stressful as you won't have to worry as much about being in people's way.

There is a 33in size limit, better look here: https://www.ns.nl/en/travel-information/luggage
This page has the direct Schipol to Rdam ticket info: https://www.ns.nl/en/routes/schiphol-airport-to-rotterdam

There are 5 ICD trains every hour direct and nonstop from Schipol Airport to Rotterdam. Take one of those. Don't take a Eurostar as they have required seat reservations, or an IC train as it takes longer and makes stops. The ICD takes only 26 minutes to Rotterdam Centraal.

Are you traveling with someone else are you going to handle all that by yourself?

With my wife. I understand that there is also ticket kiosk and travel information desk in the airport.

Question does first class have the same baggage method as second class.

Yes, same luggage provisions. 1st class has fewer seats in the carriage, so perhaps more space available.

BTW, in all my trips to Europe, I have never worried about finding space for my luggage on trains, and I have traveled "heavy" several times.

I have had trouble finding space for a 24"-25" bag in second class carriages on French trains in the month of August, when it seemed the entire population was on the move. Twice I had to sit on a flip-down seat in the vestibule so I could move my suitcase out of the way of others at every stop. There was no place to leave it that was out of the way of other passengers. It was annoying, since I had my own seats on those trains, but it didn't kill me.

You’re overthinking this a bit I’m afraid. I frequently travel on the train line between Schiphol Airport and Rotterdam. Lots and lots of people who board the train at Schiphol Airport have luggage and it’s never an issue. Where you can place your luggage depends on the type of train. The Schiphol -Rotterdam route is served by 2 types of trains; the very old trains that require a few steps to board the train and the brand new trains called ICNG which are step free. Both types of trains have luggage racks for large pieces of luggage and a rack above the seats for hand luggage.
If the luggage racks are full, just place the luggage near your seat. I know the rules say that you mustn’t place luggage in the isle or on seats, but that’s exactly what people do and it’s never an issue.

Thank you all for the information.