To rename the file "titles.txt" in the current directory to "music_collection.txt" you would type
To move the file "students.txt" from the current directory to the directory "/school" you can enter
mv titles.txt music_collection.txt
The "." at the end means: place here without renaming. If you want to move and rename a file a file at the same time you would type:
mv students.txt school/.
mv students.txt school/2nd_grade.txt