Simple explanation?
Install Checkpoint on your 3DS, use it to backup your save data for Omega Ruby or Alpha Sapphire.
Move your save file to whatever PC has PKHex on it. Drag the save file (named "main") into PKHex.
Click on the "Tools" dropdown menu in PKHex, then "Data", then "Encounter Database" and next to "Species" is a drop-down menu that currently says "Any". Replace that with Ditto by finding it in the drop-down menu or type it in to save time. Click "Search!" at the bottom and right-click any Ditto, click "View" to add it to the main box's screen and close the encounter box (it'll say "Database" at the top of the window). Drag the Ditto to any slot in the box. This Ditto will not have perfect IVs, but you can click its "Stats" tab in the view section on the left, change all IVs to 31 and just drag it back into the box to make another copy. Older generations IVs were tied to PID, so you had to change that, but Gen 6 only uses PID for determining shiny status and not much else, so you can change the IVs how you like without worrying about authenticity, but for breeding it doesn't matter if the Pokemon is legal or not, only what IVs and egg moves the parent actually has.
If any of this sounds like too much work, it's because in my attempt to be specific and clear has backfired. I am very bad at simplifying, as you can tell, but it's actually a ridiculously easy process. In fact, in the amount of time I explained this to you, I made a Ditto myself just so I had all the right instructions.
If you don't feel like going through it, you can private message me and I'll just trade you one. Doesn't take much to generate them once you know what you're doing.