Connect your iPhone/iPod touch/iPad to your computer. Open iTunes (1).
Click on your device in left side iTunes menu once it is connected (2). Click the "Apps" tab from the top menu (3).
Scroll to the bottom of the page to see the "File Sharing" section (4). Click the "Sub Video" app (5). Click the "Add..." button (6).
Select the MVA file and MVB file for the video you want to copy (7) and press "Choose" (8). iTunes will now copy the video you selected over to your device.
To select more than one file, click on the first file, then hold down the command key on Mac OS X or the CTRL key on Windows and click the on the other files you want.
You must copy both the MVA and the MVB file for each video. If you fail to copy one over, Sub Video Player will not import the video and you will have to re-copy both over again.
You do not need to select only one file at a time. You can select multiple files (7) and iTunes will copy all the files you selected over to your device in one pass.
Open Sub Video Player on your iPhone, iPod touch or iPad. Tap the "Library" button (9) and then tap the Sync button (10) to get Sub Video Player to import the new videos.
You can remove videos that you accidentally added by clicking on the file (11) and then pressing the delete button on your keyboard. A dialog will pop up to confirm that you want to delete the file. Click the "Delete" button (12). Once the videos have been imported into Sub Video Player you can only delete the videos from within the app.