Changing templates and fonts

I'm new to Squarespace. I'm just about to start the 14-day trial. But before I do I have a couple of basic questions. First, if I'm unhappy with a particular template, can I change it to another template without losing all the copy and images I've used in the first template. Second, can I change the font in a particular template or are particular fonts locked into a particular template? Apologies if these question shave been answered elsewhere. Thank you.