Hi, and welcome
This is actually two questions: (1) how to create a variable (more generally referred to as an object; and (2) how to assign a value to that variable based on a test.
The first is simple: use the <- operator. In your case, since you don't yet know what the value that the object will take before the test, you could simply assign a "not applicable" value to it and change it later
my_variable <- NA
but that's not the best way to start.
Create, instead two variables, one for percentage of students qualifying for lunch and one for those who are English learners. Then review your notes and text to see how to perform a test for the value of a variable.