You can find a great batch file creation tutorial here:
http://www.computerhope.com/batch.htmFollow the instructions under the Windows section (using Notepad to create).
However, there is an easier way to run PC games from MA. It also eliminates the ugly command prompt box that pops up when using a normal batch file. This is for Maximus Arcade version 2.10 Final only, where shortcuts have been fixed (previous version were broken)
Simply right click the .exe file for the game that you want to run and then in the context menu select "create shortcut". Then right click on the shortcut and select "Rename". Whatever you rename it is how it will appear in the Maximus Arcade list.
Once that's all done, I make a directory in the MA folder called "batch files" and then drag all of your shortcuts you created there. Then in Preferences set that folder ("batch files") for the rom folder to scan. Make sure the # 3 option is selected after you set it to point to the right directory:
http://www.maximusarcade.com/max.htm#scan (also make sure you have "batch files" selected in the dropdown above.)
I only create batch files if specific commands need to be run if the other method does not work properly. But 90% of the time you don't need to.
Hope this helped!
~ DeLuSioNaL29