What is the most simple and easiest way to backup and restore on oracle 11g

Use RMAN to back up to the network share. An export is NOT a true backup as you cannot perform a point-in-time recovery with it. XE comes with backup scripts that you can just schedule with AT or similar, the documentation says:

To schedule automatic backups, use any operating system or third party task scheduling software to run the supplied backup script for your platform

If you are running the database in archivelog mode, then the archived redo logs are your "continuous export", so you would ideally want to have those on seperate disks from the DBFs, and hopefully mirrored. RMAN will back those up too. As you say you have a single disk, well, this is a judgement call you will need to make - I would say if the data is valuable enough to back up, it is valuable enough to run on server-grade hardware.

Cold backups, like hot backups can be taken in different ways. One is by using rman - recommended - the other is using OS tools like copy/dd. Next to that, storage based snapshots could be used. So in order to know how to restore, it is important to know how the backup has been made.

If the backup is properly made using RMAN, there is not much more to do than starting your instance, connect to the catalog, or find a snapshot controlfile that contains the backup administration, connect to the instance and issue a restore database command. If it is an OS tools backup, use the same tool[s] to copy the files to their original locations and start the database, once done.

There are many potential pitfalls using cold OS tool backups. I have seen situations in which the admin told me ....

'eventually we switched to xcopy because we got file locking problems ...'

instead of looking further. He missed the point that the database was started during the cold backup. This is one of my reasons not to be a big fan of COLD backups. They make me shiver.

Be smart and carefully read Oracle® Database Backup and Recovery User's Guide 11g Release 2 (11.2) It is worth every minute you spend studying it. Oracle backup and recovery is not hard, there are just a lot of options.