The point was that I practiced that opening section a thousand time in a row. When I'm rusty, I still noodle on it a bit because it still show how rusty I can get with that arpeggio.
Find a few chord changes and just do them over and over again: C, D, A then G, D, A then E, A, C and so on....
Not that you have to these actual patterns but I did a bit of that when I started. Chord changes seemed to be kinda naturally for me when I knew the chords and that's kinda the point: You want to get used to your fingers landing at a certain location.
Make up little patterns and hammer them over and over, then vary the theme.
It's funny, one of these little chord changes I used to mess with when I started is still the first couple of chords I do when I pick up a new guitar to try out or what I strum after I tune: (open) G, D, A...and maybe an E for fun.