You won't find the reward on CO's site because of the way it mixes partners. You can call and should be able to talk the agent through the specific flights and get what you want.

To find the flights I started by searching EWR-MUC on 9/16 as a reward trip with the return on 9/21. That gave me the details for the outbound segments. Then I searched for EWR-AMS on the same dates, picking a random flight for the outbound and paying attention on the return. Because it is a partner flight you'll need to scroll down on the page a bit to see it. I then used nwa.com to find the MUC-AMS flight by searching a r/t reward from 9/21 to 9/28. Once you have the details the agent can input them and assemble it correctly.

If you are doing it as business both ways it will be 100K points. CO will only let you hold it for ~72 hours but there are a couple ways to get the points from AmEx to fill out your transfer need if you don't have enough. There is a Points Advance feature that is a minimum of 15K, depending on the level of card you have in the MR program. Or you can buy the points from CO or AmEx. They are about 1/3 the price from AmEx as they are from CO so buy there if necessary.