When learning copperplate, you find the need for different types of guidelines as you progress through the different stages of learning and as you discover your preferences. There's a LOT of options available online, each a little different. Here's 3 free printable PDFs for each stage of your progress, including my own:
1. For absolute beginners
Nice basic instruction on how to use guidelines and clearly marked header and baselines to avoid confusion. Perfect for your first time. I only wish the lines were lighter so they wouldn't interfere with my letterforms, which leads me to:
2. For when you're a bit familiar
but still learning the letterforms: Modified version of Nita Whitfield's
These were originally very dark, so I took, smushed them together vertically to shorten the line-height and made the lines lighter. I used them for a long while learning the script.
Anintran has a nice collection of more guidelines.
3. For regular practice
My own guidelines
Once you know your ascender and descender heights well and just want a no-fuss paper that just helps you maintain horizontal and diagonal angles, use the one I made and use regularly. It's got a small x-height, small line-height and very light guidelines so you can see your writing.
What paper to print them on?
I print them on Canson layout paper. If you use regular printer paper, make sure you're using sumi ink and not India ink, because the latter is quite a pain on thin papers.