Oh, you have 3 children of different ages using it? That is great! Congratulations! You should start using it too! You would be a model to them and they may try to be better too and they will

just like my son or others did. We also have parents that really amaze us and are models for the rest of us. With busy lives, no musical background, they play tough musical pieces just because they like it and play whenever they can, even when children are asleep

.
I started as musically illiterate about a year and half ago and have been playing myself.
I recommend you read Hellene's first book,
"You CAN Be A Musician" (free)
, in case you haven't already. It gives any user the background needed to start using the software and also it explains why Soft Mozart is structured this way and what is the reason for each part of it.
Also, her
posts about teaching toddlers
is great as mothers have shared their experience too.
NOTE: It is very difficult to write in a manual or guide something for all ages and levels. It would take too many pages and it is really not possible to help each individual that is why we have this forum. We are also working on an elearning free platform meant to be even more helpful and ease the communication between the student and Soft Mozart teachers and give a better way to use the curriculum online.
Shall we start with the smallest one

?
For a 2 year old,
this answer
may be a place to start teaching. It has videos that show you what to do. Also, on
Hellene Hiner's YouTube Channel
you can search by age and find different useful videos.
The curriculum guidelines for early learners are here, for Semester 1:
http://softmozart.com/forum/54-semester-september-1-december-31-of-2012/5301-early-learners--24-months-to-5-year.html
For the 5 and 7 year old you may look at Semester 1 guidelines for their level - Beginners 5 to adults:
http://softmozart.com/forum/54-semester-september-1-december-31-of-2012/5303-beginners-age-5--to-adults.html
. They are made by Hellene Hiner and the order of the tasks is made in a way that it develops abilities the student needs to play piano.
Please make a separate thread for each child in this section, Progress Diaries:
http://softmozart.com/forum/33-progress-diaries.html
Wherever you have a module, like Note Alphabet or other in the guidelines, use the User Manual to see the shorcuts and meanings of characters and symbols. Then try it and take a screenshot or picture of the results over time. It is always best to have results written in a notebook when using Soft Mozart modules. This way you see progress day by day and with each use and you can encourage children.
A new curriculum, for this academic year will be available next month. Until then the one from last year is very good.
Hope this helps more
Andrea