How can I take a sample from CDF and then calculate manually chi-squared statistic?

I am not good at R. I have a problem that I must solve it in R. I have two CDFs. One of them is for my original data and another is for rgamma. now I should take a random sample from these CDFs and calculate the chi-squared statistic manually to identify p-value and GOF. I do not allow to use the chi-squre package and I must do everything manually. is there anyone to help me, please? here is my data:

x<- sort(d1)
CDFx<- ecdf(x)
d2<- rgamma(length(x),0.25436673129,0.00001157445)
y<- sort(d2)
CDFy<- ecdf(y)