To expand on that...
Start by with the folder the import created. Highlight it, then drag it where you want it to go (...the Bookmarks Menu as suggested above, probably) if it's not already there.
Then expand that imported folder by clicking the triangle next to it. Now you can highlight and drag folders or bookmarks wherever you want them to go.
It can be a bit tricky. If you hover over another bookmarks folder with something "in tow" that folder will open. It happens quickly. If you're rearranging the order of individual bookmarks, a line will appear between the two where your "in tow" bookmark will be placed if you release the mouse button. It is possible to get that line and drop a folder between two folders, but you have to be patient, and quick! Patient: don't release unless you see the line. Try to "sneak" in from the side till you get the hang of the speed, Quick: then "dive bomb" and drop.