Most things you learn, you want to start from the basics and move to the more advanced topics. The problem with languages is that it's easy to mix up the basics and the advanced topics.
It's tempting to think it'll be like math. Learn the little things, the individual words, the bits of grammar, then put them together. That's backwards. With language learning, the little things are the advanced topics. Individual grammatical concepts and even the meaning of specific words, that's the hard stuff.
The easy stuff is a sentence. You can understand the sentence without understanding the function of its parts. You can know what I mean without knowing why the words I'm saying mean that. In fact, you can understand a sentence without necessarily understanding any word in the sentence.
If we're going to start from the basics, we have to start from meaning. You can't ask why Maria parvum agnum habuit means "Mary had a little lamb" until you know that it does mean that.
Example: try to translate a sentence you don't understand by using your knowledge of grammar and a dictionary for the vocabulary. Now try to figure out why the grammar and vocabulary of a sentence you do understand fits together to make the meaning. Which was easier?
If you're learning, what all this means is that it doesn't really matter if you get the grammar of a sentence, so long as you get what the sentence means. The little things will settle into place over time. Meaning first, then the fiddly bits.
Most Latin textbooks put the cart before the horse. If you're teaching, have sympathy for the student and their perspective, and put the meaning first. Teach sentences before you teach grammar.