Editing Text Frame

I want to add some Performance Notes at the beginning of my arrangement; so, I inserted a Text Frame; however, I cannot figure out how to change the size of the Text Frame box to allow for more than one line of text. I'm not going to write a novel, just a few short sentences. How can this be accomplished? Also, because I probably did this incorrectly as I just selected the first measure of the top "voice" line; how do I make sure this Text Frame is "System Text" (AKA - gets put into the score and ALL parts and not just the top voice)? I'd really appreciate some help if someone else has figure this out already!! Thank you! - TIm

I feel like this is probably a pretty "safe" space, so if you have an answer - feel free to email me at: timothylmaguire@gmail.com. I really want to learn how to do things like this and I couldn't find anything in the online Handbook or already in the Discussion/Help Forum.