Hi Tim
Both the layouts are completely different and using different PHP codes and style . If you want to change the JA Nuevo template blog layout , You need to compare both blog files codes from /a html/com_content/category folder . And arrange the code + modify them . Also, you need to check the CSS style used in JA Uber and then apply it in Your template via custom.css . This work too pretty efforts to apply changes . If you are not a developer i suggest you to hire a developer for such work . You can also try out JA custom services and get a quota if you wish to use this service .
Here is Link