I had a 32-bit PC with Ubuntu 16.04 but couldn't update directly to 18.04 because the latter is for 64-bit. Nevertheless, I found some code which allowed me to do so, and now I can run 64-bit programs (but slower). As I'm not good at coding and it took me a whole afternoon, I want to make an ISO image to boot and run Ubuntu 18.04 temporarily on another 32-bit PC without installing it over Windows.
How can I make the correct ISO image, and what files should be in it? If the modified ISO is already available in a repository, please let me know. Thanks.