adding 2nd blog

I am wanting to add a 2nd blog, but before I did I wanted to make sure I wouldn’t be screwing up anything with my 1st one if I did.

I am new to this and have had help from this site, so being new, will I be messing with my 1st blog stuff? I have been reading the codex, but before I get going, i just wanted to know how difficult it actually is.

Thanks in advance
Stef