How do I get the commands I specify to run automatically when I boot from Raspberry Pi3?

You can insert a command script in the /etc/rc.local file or a script file to run in the /etc/profile.d/path.

Or check the url below. This is the content of registering the start command in Raspberry Pi. It's similar because it's Linux-based anyway.

http://www.rasplay.org/?p=4854

What do you mean by the command you specified? Are you talking about the command lines you entered? If that's the case, I have to write a script and make it run after booting, but I don't remember at what level... I think it depends on what the script wants to doOnly