I'm going on a trip next month so I bought a new camera. This is not my first camera but it is my first "real" camera, first  mirrorless camera and first time I've used a camera in a few years after my first one died. My first camera was a Nikon, I don't remember the model, but it was a bridge camera. The camera I bought is a Canon EOS R10; along with the RF 18-150mm lens (kit lens) and the RF100-400mm lens. (I am not looking to buy anymore/a different lens right now) I've been watching a lot of videos/tutorials on YouTube but it's a lot of information and very overwhelming. I've barely learned what aperture, shutter speed, and ISO mean/do. Please give me your best, must have advice for shooting decent photos.

 So far I've struggled with 

\- getting the camera to focus at times (the whole screen will be blurry and I don't understand why or what I even do to fix it. I just fidget with it until it becomes un-blurry)

\- over exposure (yes while on the camera but also when I import my photos to my tablet it takes a good photo and punches the exposure up and I have no idea why)

\- under exposure (when I have the settings where I think they should be for what I'm shooting it looks too dark so I'm forced to sacrifice a setting, usually ISO, to get brighter photos but it makes it grainy)

As a side note, we'll be stopping at about 4 "zoos"/wildlife parks. I love wildlife photography, so I'd like to try to get some "wildlife" shots. I'd also like to take some portraits of my bf and his son, and nature shots of flowers/landscapes. I also have a tripod and would like to try and get some night shots with the stars. I'd appreciate any specific advice for these types of photography.

TL,DR; My new camera is a Canon EOS R10; RF18-150mm and RF100-400mm lens. I'd like to shoot wildlife, portraits, landscapes, close-ups, and nighttime/stars. Please give me your best general or specific advice. (Bonus points if you explain it like I'm 5 because all of the new information is overwhelming) Pictures of fur babies as taxes(and examples of what I've been able to shoot so far)

What do I absolutely need to know as a new-ish photographer?