How to split residuals into groups for the Brown-Forsythe test

#1
I have the following data
id 1 2 3 4 5 6 7 8 9 10 11 12
num. responses 16 14 22 10 14 17 10 13 19 12 18 11
cost 77 70 85 50 62 70 55 63 88 57 81 51

I fitted the linear regression model and I got the following residuals:
5.22478992, 4.76260504, -6.38865546, -2.16176471, -3.23739496, -5.04411765, 2.83823529, 1.03151261, 6.41806723, -1.69957983, 2.68697479, -4.43067227

I want to preform the Brown-Forsythe test and I am suppose to split the residuals into two groups using the following method "Begin by letting group 1 consist of the residuals associated with the n1 lowest values of the predictor. Then, let group 2 consists of the residuals associated with the n2 highest values of the predictor (so n1+n2 = n)." I can't understand how I should apply the method above to split the data can someone explain it to me.