Daisy

Hi everyone. I've recently bought a 2004 50cc Gilera DNA. I've been told the starter motor needs changing. I've bought a replacement, taken the engine cover off. Now what? This is my first bike, I haven't ridden it yet and feel like I've failed on the first job! This is way out of my skill range. Give me beading or paper crafts and I'm happy!! One 'friend' said the back wheel needs to come off, another said the center stand off. Any advice is welcome! 43f embarking on a mid-life crisis!