When you get your new LTS system of Ubuntu installed, browser around this site which should help you get around your system at a comprehensive level.
Ubuntu has multiple flavors. Scan through this list and find one that you like most.
Your system has detected a new version of ubuntu and is prompting you to update. It is better that you stick with the LTS versions as they are supported longer than the non LTS versions.
Installing Ubuntu is actually easy. You will be able to get through it even if you claim computer illiteracy.