Luggage Storage at Rotterdam train station

Yes, you can store luggage at Rotterdam Central Station. The storage is close to platform 16. Look for the sign with "kluis" on it.

Rotterdam is the nicest and newest train station we saw in The Netherlands. When you come into the main lobby, walk to your left to get on a Tram(7 or8) and take it to the last stop by tne river. The riverboats leave from that area. We used our OVClipkaarts for both the tram and waterbus but they also took cash on the waterbus. Enjoy Kinderdijk; it is a beautiful spot to take a stroll by the 19 windmills.

It is doable, but I doubt whether it will be the most pleasant day of your trip after a long flight.
The easiest way is to pick up a bus in Dordrecht. Dordrecht has a very frequent rail connection with Schiphol airport, either direct or with one change, taking 45 mins to 1hr10. There is an hourly direct bus service with Kinderdijk, leaving in front of the railway station, bringing you there in around 40 mins. (Other buses involve a change, making it more complicated.) According to the website of NS (the Dutch railways) Dordrecht station has lockers. It is also a stop on the hourly Intercity to Brussels.
The Intercity Brussel has no reservation, so your ticket is valid for all trains on that day, including any train from Schiphol to Dordrecht, making it the most flexible option.

I disagree with Ton. Getting to Rotterdam from Schiphol Airport is faster and easier than going to Dordrecht, which may well require a train change in Rotterdam.
And the boat trip to Kinderdijk is a relaxing and beautiful part of the excursion, much nicer than going by bus.

My worry is that everything must be done on one day, between arrival at Schiphol and getting the train to Brussels.
Getting from Rotterdam Centraal station to the Waterbus involves a tram in Rotterdam. After Kinderdijk OP must get back to Rotterdam Centraal (ferry, then tram) to fetch the luggage and then get to the train. And all that after a long flight: tired and possibly jet-lagged in unknown territory.
The Dordrecht option is less attractive, but a lot simpler.

Thank you everyone for your ideas. I was only planning on going to Kinderdijk on my way to Gent after my flight. I am now thinking i may just go straight to Gent and leave Kinderdijk for my last day after the tour and take the train and then take the water ferry/taxi to get to the windmills. I was just trying to use all my time wisely. I think I will just get myself oriented to Gent and get over the jet lag and then I will be able to go to Brussels on the following day.

Is there any better place to see windmills in their original location? I have already been to see the Zaanse Schans Windmills, Marken, and Volendam when I was last in Amsterdam about 10 years ago. I would like to see some new ones. I am a more experienced international traveler and enjoy going out on my own now. The last time i went on a pre-arranged bus tour.

Kinderdijk is unbeatable and with more time at hand relatively easy to reach using the Waterbus.
There are other original windmill complexes, such as my favourite at Schermerhorn, near Alkmaar, dating from around 1640 for draining the Schermer reclamation. That implies a train from Amsterdam to Alkmaar and then an hourly bus.
Something quite different are the historical windmills of Schiedam, near Rotterdam, for the once important gin industry. Five minutes by train from Rotterdam Centraal and then a short walk to the city centre. Nice city, totally overlooked by tourists.

Ton,

Thank you for the suggestions for the other areas with windmills. I will have map out that location near Rotterdam and Alkmaar. I enjoy reading all the suggestions you post on any questions posted in the Netherlands Forum. Thank you again.

This real-time public transport planner might be of use.