Is this forum not widely used? No replies in four days after the post would suggest this isn't the best place to get help?
Hi Grant, The forums are very active.
A logo change is going to the content holder or part of the template where the logo is and changing the image html. This is more standard html and css knowledge and people spend a long time learning this and a wealth of information. I do not use templates for example so I can only give a broad answer on how to edit html for example. If you need to learn html and css stuff there is a million and one things out there. In the guide section on these forums there are docs about things and also links to guide sites like BC Gurus to help learn BC and this stuff.
So it is quite hard to post a helpful response so I guess that is why you not got a reply.
There are some free templates on my site - bcappcenter.com - It could be a good start to look at those so you can get used to customising a site.
Every BC template is also made differently so it is a exceptionally broad subject you have asked.