What should a guitar beginner start with? How to approach practice by thinking from your 'favorite songs'

I bought a guitar and started practicing using instructional books and videos. But there's so much to learn, and I don't know ...

Music Theory for Beginners Part 3 | What is the difference between "C" and "Cm"? Understanding chord structure through guitar

When practicing songs on the guitar, various chords like C, Am, and Em appear.Even if you remember how to press the strings with your fingers, don't you ever wonder, "What does this little 'm' mean?" ...