You really should have a computer. The iPad is not a replacement for one. You would need to connect to iTunes, authorize the computer and sync content over so you have it stored in iTunes (backing up to an external drive is a good idea as well) and an iPad backup file would be created as well
If anything happened to the iPad your content would be lost. You would be reliant on the other computer and one should be syncing regularly so it would be hard to do.