Alberta Infant Movement Scale - AIMS

Hi i am trying to get help from people well versed in using the AIMS . i am not able to understand the method of scoring . I do have a book explaining the same . Any help of any sort appreciated

Its fairly simple

Select a skill the infant is showing you in prone i.e Prone Prop head to 45 deg. (Yes) Look at the next skill, can they lift and maintain the head above 45 with elbows in line if yes move on, if no, look at the next skill, if they cannot do the next skill (Prone mobility) then they score 3 points for Prone. Dont worry too much about the "window" as this can confuse you. They either can or cannot do the skill, if they can they get a point, if not, check this is their ceiling effect and move on to the next "study"(Supine) The points dont have to be consecutive i.e. can do pivoting and swimming but not reaching from forearm support. Just dont score the latter.
Add these all up ie, 3 for prone, 4 for supine, 2 for sitting and 2 for standing
= 11 points. This gives you an age equiv score of approx 3 months or percentiles based on age.

hope this helps