If the author’s note is extensive, then putting it in its own chapter is a good idea. Your readers who care about such things will read it. A lot of readers don’t bother reading author notes, and this will make it easy for them to skip it. However, if it’s really important that your readers read it before the story, then include it at the beginning of your chapter, and keep it brief. Make your point and move on.
I usually read author notes, but if it’s long and rambling, and I have no idea where they’re going with it, then I skip it. I care if they want to tell me to forgive the bad grammar, or if they don’t know whether a character should do what they did. I don’t care if the author thought of this story one day when they were walking their cat through a park and they saw a flock of birds fluttering past, which reminded them of dinner at Grandma’s house last year when those birds landed in her pond. This makes me think the story is going to be pointless and rambling as well, so unless you have a specific message for your reader, better to skip the note altogether.
A lot of people like quotes. I personally find them annoying. I want to get on with the actual story, not waste time on some words taken out of context and written by somebody else.