Note also this: Off-topic posts will be closed easily. We aren’t going to teach you electronics, but when you attach a KiCad project as ask comments about it, we will consider the thread to be directly related to KiCad – until some point.
There are many beginner project threads here already which pretty much repeat the same basic things: ground planes and ground connections, bypass capacitor placement, general component placement… but if I recall correctly, nobody has collected links to them to make a FAQ article.