Oh. Here are some possibilites :
1.
Open My Computer.
Open Local Disk (C

.
Go to program files.
Open the file named "Steam".
Open "SteamApps".
Open "".
Open Counter-Strike:Source.
Open cstrike.
There should be an icon that looks like a notebook. One should be called mapcycle. Open it.
Save the original copy to the desktop.
Delete it and put in the order you want. make sure that there are no caps, full stops or spaces. make sure every map name has its own line.
If it screws up, open the original copy, Copy and paste is onto the mapcycle page.
2. https://www.youtube.com/watch?v=IBucXc4ol-w