In cases like this, the first question I would ask is: What is your motivation of learning the target language? Are you doing it mostly because it is required by your school or are you genuinely interested in the target language and culture?
The answer may be "both." of course, because students rarely have a choice, but it helps, if there is also an intrinsic factor.
Unless you are preparing for a particular exam, the fact that solutions are not provided leads me to the conclusion that the materials are not worth spending your time with and it may make more sense to look for alternatives. Personally, I am a fan of the language learning philosophy developed by Lýdia Machová:
It's all about having fun with the language and exposure.
For example, if you like reading, try reading a book you already know and like in your target language. If you are trying to learn a grammatical structure for an assignment, just pay attention to when it is used and maybe have the book in your own language close to compare side-by-side, in which contexts the structure appears and how this might differ from you own language.
Watch TV shows either originally in your target language, even if you
don't understand anything at first, you will get used to the tone of
the language. If you must, use subtitles. Or re-watch a show you
already know in a dubbed version.
Play a computer game you like and switch the language to your target
language. If there are many dialogues (and you roughly know whats
going on) this will enhance your reading skills.
Find pod-casts in the target language about a topic you are
interested in. If possible/required reduce the speed of the podcast and listen to it more slowly to help you understand what it's about.
If possible find someone speaking your target language that tries to learn your language. Ideally someone of the same age and with similar interests. I've heard this is sometimes even set up by teachers for entire classes and works even better now, because most students are equipped with the required infrastructure anyways. There are also apps who provide these "language tandem" options. You could also opt for a more classic approach and find a pen pal (which is then more about writing than speaking).
Find a language learning app that you like (I'm not going to advertise any here, but a quick search on the internet will give you the hints you need). Most of them are based on "gamification", which a playful approach to learning, which appeals to everyone but especially children.
Also, something I can only recommend to make vocabulary come to life a bit more is acutally labeling objects in your house. But try to be specific and add some characteristic of the object: "blue door" "large refridgerator".
Now you can return to the provided material and hope it answers the questions you may have concerning specific grammar and vocabulary topics.
Of course, I am super aware that these approaches have not been developed especially for children and sometimes the way languages are taught in schools may not actually be suitable for anyone to learn a language and be able to use it, but language learning is really about the invested time and making progress along the way. Hope it helps.