All previous answers are correct.
I'll just simplify it by doing it in single lines...
First, let's assume your *Insert Name* is 'YOURNAME'
1. Start > Run
Type "cmd" (without the quotes) then press {Enter} or press [OK]
A black window should appear with the a blinking cursor
2. Type "cd\users\YOURNAME\My Documents" (without the quotes) then press {Enter}
The text prompt should be changed to what you have typed
To see the files in that directory, type "dir" (without the quotes) and press {Enter}
To know how to use other switches of "dir" command, type "dir /?" (without the quotes)
To rename a file, say there's a file called 'myfile.txt', type "ren myfile.txt myrenamedfile.abc" (without the quotes) then press {Enter}
It is now named 'myrenamedfile.abc'
type "dir" (without the quotes) then {Enter} to see if it is
To copy a file (or files) to another directory (or to another filename), type "copy myrenamedfile.abc mycopiedfile.log" (without the quotes) then press {Enter}
To know how to use other switches of "copy", type "copy /?" (without the quotes)
type "dir" (without the quotes) then {Enter} to see
To delete a file, type "del /?" (without the quotes) then {Enter} to see how to use it
Cheers!