Hi bellevuejim,
Upgrade from T3v2 to T3v3 is a risky progress.
1. Please BACKUP your site.
2. Install latest T3v3 (1.4.3) and JA Mero packages (not the quickstart package)
3. Disabled T3v2 plugins
4. Switch JA Mero as default template style.
5. Config other settings as the JA Mero quickstart package (You may need to install a JA Mero quickstart in your localhost to compare the configuration)
Template config, module positions have to be redone manually, so do take your time to see the userguide too which covers all the extensions / menu items and their backend configurations as used on the demo site.
Regards