The から portion marks the text before it as a reason. It’s because he can’t take his hands off the steering wheel, he’d like Yotsuba to act on his behalf.
The な is typically seen at the end of a sentence, and has a sense like “you know?” at the end of an English sentence.
You could translate this as, “Dad can’t take his hands off the steering wheel, you know, so please wave on my behalf.”
Note: Don’t read too much into the meaning of “you know?” in English, as that’s just an example of an approximation for な in English. Read up a bit on the sentence-ending particle な to get a better idea of its meaning, then you’ll get a good feel for it over time as you encounter it more.
For a little more context, から is, in isolation, something that can be translated as “starting from <state, place, time>”, but in practice, it often introduces a reason, as Christopher mentioned.
It’s a very common usage and you’ll see it everywhere, any time someone wants to establish perspective for interpreting what follows.
At this point, there are so many combinations of things you haven’t seen. Keep working your way through native material, and you’ll encounter things like this often enough that you’ll better recognize it even when it’s a new combination to you.
Sorry for taking ages to reply. I would like to read along at (roughly) the same time.
I’ve also started my first ABBC, which I noticed you are also doing (ゆびさきと恋々 ・ A Sign of Affection (Absolute Beginner Book Club) - Reading Now!). I’ll try to do both in parallel, but I’m a bit short on spare time this month so will see how it goes!
It’s okay, we can take our time, if it’s too much for you, you can just pick one and do the other on the side, I think I will focus on the ABBC and read Yotsubato once and a while or maybe just one page per day
(Absolute Beginner Book Club) - Reading Now!