Kweku, the raw score means what you had in the five subjects when they marked your exam paper . This could be either 70% or 72% or 80% or even 100% all depends on what you had. Now they add the raw score of English, Maths and Science/Social Studies depending on what you want to do in SHS. That is if you want to study Science then science science is what is added in addition to other 2 subjects you did best in. After which all the marks are added up and the resulting score is what is used for the school placement. Am going to give you an example if student called Jack had all ones in his 5 subjects but in the raw score he had these scores 72, 70,75, 74 and 70 and a second student who had only four ones out of the five needed these were his grades 2,1,1,1,1 but his scores were as follows 67,85,80,77 and 95. Now after tallying the scores Jack had 361 and John had 404..Now though Jack had seemingly better grades John had a better score therefore it stands to reason that John will likely get the school first if they applied for the same school and same programme..
Now lets assume they both applied for science in a school called 85 SHS. This school has space for 150 students but the students who chose this school was 500 in total then the question is who will get the school. So the placement starts from the highest score among the students going down until it gets to the target number of having the 150 students names needed on the list for 85 SHS.
The reason I cannot tell you your raw score is because the grade in terms of grade 1 and so on comes from a range. An example is
grade 1= 70 and above
grade 2= 65-70
grade 3= 60-65
grade 4= 50-60
grade 5= 40-50
grade 6= 30-40
Note that the grades also depend on the general performance in a particular subject so that is like to change so in a situation where a lot of students did very well then grade 1 might start from 80 and above therefore shifting the other grades for that subject alone.
Let me know if am not clear.