Why can't I use crewMember.name?

So basically in my own words the variable crewMember is not even pointing at the object or the object element. The loop literally iterated over the objects crew and grabbed the member and converted it to a string and put it in the variable. The variable is just that a variable with a string that was grabbed from an object but doesn’t point to the object. That is why we have to point to the object all over again by using spaceship.crew[crewMember].name. ← this code is the same as writing spaceship.crew[‘captain’].name only it is using the string already in the variable rather than the user having to write it out.

Also, this is the end of the Objects Lesson, is there anywhere that I can practice what I learned here. Like something that has challenges tailored to this beginning part of objects. I feel like I grasped it but I need to practice it a lot and I want to practice before moving on to advanced objects.