Hello and welcome to the forum. There are a ton of free BSG models (both old and new) throughout the net. You can find many of them here as well.
There are also quite a few people that can help and give you advice if you are having problems.
Here is a website where you can find some old BSG models (to include the original Galactica):
http://jleslie48.com/gallery_models_scifi.html
That should keep you busy for a few days.
I look forward to seeing your work.
Once again, welcome aboard.