Help for first project

Hello, my name is Renan and I am starting the studies on the platform, I work with different applications with arduino in my university, I am interested in Ardupilot and wanted to take some basic doubts of who is starting, if there is already this topic please forgive me yet I’m adapting to the forum.
First, my goal is to make a standalone drone, with some additional sensors to the Ardupilot kit, what is the best way to use arduino with the Ardupilot software / hardware?
And what is the best kit to buy for an autonomous drone? (Important to point out that my goal is to focus the studies of the Arduino platform, so I really wanted an indication of the shortest path I should follow to have an Ardupilot autonomous model)

The best “kit” at the moment is probably a solo from amazon or the like. If you want to build a multicopter yourself (more fun), there are lots of options. You need to start by deciding some performance parameters (lifting capacity, size, and endurance) then start designing your system and selecting components. A lot of people use a website called ecalc to help.
Regarding arduino, it depends on what you are trying to do.
The ArduPilot codebase isn’t written for or in arduino anymore - the name represents the origin of the project, not where it has advanced to.
Interfacing an external micro controller, such as an arduino board, is best done using mavlink. MAVLink Step by Step
I hope this helps.