Conditional formatting referencing 2 sheets

hi
i have 3 sheets one with data 1, data 2 and the other main.
the workbook is mainly bout students grades, and the courses they are taking.
data 1 consists of courses that have been taken by the student before n their grades.
the data 2 consists of column A being the students ID and column B being the course id.

i need excel to highlight the course id on the main sheet after referencing student id and course from data 2.

for example ACC410 is current being taken by student id 90012154, i need the course ACC410 on the main sheet to be highlighted in yellow text with yellow background.

another thing i wanted to kno is how can i filter out the courses that are present in the tables from the ones present in data 1 and data 2.
i need to show the grades of the courses that have been taken and the courses currently enrolled in by the student other than the ones displayed on the main sheet.