I have fairly many musician friends who actually own guitars, but as a most recent example our local congregation has a pretty sweet acoustic Yamaha that is a real joy to play, given, it is also really expensive. Mine costed like 50€ and it does not play well.
You could get one of those guitar tuners, they make tuning really easy. I can't really tune without a proper tuner myself, although there are some "manual ways" of checking that the strings are in tune in relation to each other, but that still requires for the first string to actually be in good tune
I personally have an older model of this:
Tuner | Guitar Tuner | Bass Tuner | Korg GA-1 Pretty much all smartphones also have guitar tuner apps, but they can be a bit hit or miss, but if you might find a good one for free. The korg shouldnt be much more than 10-20€ and I've found mine as a very good basic tool for tuning, had it for about a decade now.
But yes, I recommend you get some classes first, while many of the worlds top guitarist are self-taught, it's naturally easier to learn at least the basics at a class.