Here is a really helpful video on basic takedown and reassembly of a 22/45.
https://www.youtube.com/watch?v=Y4DoS8Uzc04
If you have a brand new one, the parts might fit together a little bit more snuggly, and you might need a rubber mallet to get the barrel off and on. Other than that, its a straightforward process once you know what your doing. Plenty of other youtube videos on this as well.