Mostly everything you need is here in the forum and in the docs. A lot of Youtube stuff is outdated.
The general idea is to get everything working quite well, including the filtering and move on to Autotune.
Component selection is very important - some builds are never going to work because of mismatched components and mismatched expectations.
There are often quite a few test flights, particularly with the bigger props.
And the flip-side is : a good build with plenty of time on the bench going over parameters before fight might only need 1 or 2 test flights before being fully tuned and ready for work or play.
The tuning guide, along with the Initial Parameters section in MissionPlanner
https://ardupilot.org/copter/docs/tuning-process-instructions.html
Harmonic Notch Filter
https://ardupilot.org/copter/docs/common-imu-notch-filtering.html
Some wiring info