Create ISO
To create an ISO-file choose "Data/DVD" at startup of CDBurnerXP Pro. To reopen the dialog, click the new-button 
in toolbar
Now you can create your ISO file on the same way as you do it with a 
Data-CD.
After adding your files you can edit the ISO Image Labels. To do that, go to Disc 
Set ISOImage Labels...
The given information does not have any function (apart from the title you can also see in Windows explorer), they are just used as additional information for your ISO file.
Then go to File Save image as ISO file.
To open the ISO labels dialog again, click "Set Labels".
To add a boot image, click "Boot Options". An explanation of adding a boot image you can find at "create bootable disc".
An explanation of Mode1XA and 2XA you can find in burn disc or in FAQ.
DVD High compatibility will cause a higher compatibility to old DVD readers. It does not matter in this case how big the data was you added to layout, the Image will be at least 1GB big. Note that after finishing the ISO file it may take a short while to write data to harddrive.
