How to view music files as "date modified" Win 7

[cactuslizard]

Every now and then I like to back up my files (which is always a good idea). I want to back up my music library to an external HD since it has greatly expanded in the last few months. For the sake of time saving, I only want to copy the most recent additions, but I can't figure out how to view them as "date modified".
I have that as an option at the top of my music folder, but I cannot figure out how to use it. I have choices like "select date or date range", "a long time ago", "earlier this year", etc.. I cannot figure out how to see which ones were within the last few months in descending order. I used to just click on the arrow next to the date modified button and that would switch them between most and least recent. Please help!

[Salmon Trout]

Windows 7 tries to be helpful when it has a folder with multimedia files, but you can make it behave. Select Details in the View menu and then right click any column header. In the menu that appears, check 'date modified' to show that column, now you can click on that column header to sort them in ascending or descending order. You can drag any column to a new position using the left mouse button. Using the right-click menu you can choose the headings you want.

[Salmon Trout]

Also, there is some proper music!