I completely understand, the learning process does feel like a balancing act sometimes because there is so much information to learn, even for some of the simplest sentences. The A1 level contains many essential units, but it’s a lot to take in when it’s all brand new.
Some Smart Review phrases can just be memorized “as-is” at first, without understanding all the grammar. Over time, you’ll gradually start to fill in the gaps.
I think what you’re doing is generally the right approach — it’s okay to skip ahead to more advanced Learning Notes, especially when something makes you curious to learn more. But also don’t feel like you have to 100% understand each sentence right away. With some grammar, you can just get familiarity with a concept, but not fully dive into it until later.
If you’re starting to feel overwhelmed, I would recommend redoing some of the early units, to try to strengthen your foundation. You could also spend time with “quiz mode” of Smart Review. This is easier than the flash cards so it can be used as a sort of stepping stone to get to the level of the flash cards. Don’t worry if you are still getting a lot wrong, this is expected. The system is set up to adapt to your performance, so you will get there eventually.
I also agree about being more selective about what you add to Smart Review. Only add the phrases that are most relevant to your life, or that are helpful for you in understanding a particular concept. If there are phrases in your Smart Review that just don’t feel useful at the moment, you can remove them to allow yourself to focus more on what you need right now.
Prepositions are particularly confusing because there are not very straightforward rules, so it takes a lot of time and exposure to the language to start getting comfortable with how they are used. For these, in addition to the prepositions units, I would recommend lots of listening practice with the Shorties (keeping an eye/ear out for when they are used), and adding a few phrases to your Smart Review for each preposition.
One other possible idea, if you are feeling the urge to jump ahead quite often: You could consider working through all the units first, just to get a full overview. Don’t try to understand each concept fully – just get some familiarity. Then, start from the beginning and work through more slowly and thoughtfully. Maybe after having at least a little exposure to the more advanced concepts, it will feel less confusing going through the second time.
Just some ideas!