Now, if you have followed this guide to create your petitions, you are probably wondering what they do. The Ext2/3/4 partition allows you to use the app2SD(install apps directly to your sdcard). Now some ROMs automatically have the App2SD capability... However, in most cases, it has to be done by the Apps2SD program available on the market. The linux swap is basically virtual memory for your phone when it runs out of RAM.
To back up the apps from the petition you have created and restore them back on your phone. Follow these instructions: