I suspect this program works better for adults (who are willing to work very hard) and possibly with high school students with a lot of guidance. I don't believe this is a good program for anyone younger than that.
Rosetta Stone is a good product (though more expensive than its value, in my opinion), but it is not a full program. And in the forms I've seen (it's been a few years), it does not teach the grammar at all, indirectly or directly—it uses the grammar, but not in a way that enables you to draw proper conclusions. I've never heard of anyone being able to learn grammar from a Rosetta Stone product, so don't feel bad if you can't!
Duolingo is a much better program, and it's free. It's much more complete, although I've never seen a single program that was truly complete.
Assimil is a good program, but I suspect that it works better for adults and experienced language learners than it does for children.
Michel Thomas and Pimsleur are good programs in quite different ways. I have a German-language resource list that sums up some of my opinions on those. They are both audio programs, but quite different. I think that Thomas will take you farther (if you can stand his terrible accent in both Spanish and English!); Pimsleur will help you develop an excellent accent and some real fluency, but with only a very limited number of things that you can say. Either one is fairly expensive (well, not one of the older MT audios); try to get them from your library. Michel Thomas has an app you can download which allows you to hear a lesson free, then download additional lessons ($5 for an hour, I believe). Or you can buy the whole program at a better price, if you like what you hear in the demo lesson. (Don't hesitate to buy the older lessons—I can't imagine that the newer versions add enough value to justify the huge increase in price.)
On my sort-of-site (not ready for the big time, I assure you!) I also have a number of Spanish language resources listed. (Spanish, not German, is my real area of expertise.) Some day, when I have the time, I will edit and improve this list.
If you look at my Stage 1 link - which is really a mess - you will see some helps for beginning Spanish students, using a reading method I can't find anywhere online, to my bewilderment. At the bottom of that Stage 1 page is a set of links to a number of different exercises. The "Ciudades and pueblos" exercise is the one I've worked on the longest; the "caballo" and the "planta" exercises should be usable, too. The EYC link was intended for an IRL class I was teaching, and probably not for raw beginners.
If anyone looks at the Spanish stuff and likes it, please let me know. Encouragement makes me much more willing to write lessons!