Choice is misery.
google and take a peek at the books that let you read an excerpt or a few pages
arduino programming c book
also there are many youtube video series, if you like that kind of thing. Again, try a few and see if you match up with someone you can stand as a teacher. Don’t be afraid to flunk them but give them a chance, usually a few minutes will tell you if you gonna be able to stick with someone.
Read these fora and start trying to follow along. Start working through the basic examples available in the IDE.
But be prepared to put in some time and work and honestly you’ll feel dumb from time to time - no one was born knowing this and it can be hard until it is easy.
HTH
a7