I highly recommend the following way for changing header and footer. Default header and footer is located at
In order to change header or logo just copy templates from defaulttheme to customtheme
That way you will override default header and footer content without changing default designs.
We also have a dedicated extension related to these types of changes please refer to this article.
Developing application takes a lot of time. You can support application by donating. There is no company behind this application and it takes away my free time. Every donation matters and does not matter how small it is!