I am currently working on the AR(1)+GARCH(1,1) model using R. I am looking out for example which explains step by step explanation for fitting this model in R.
library(fGarch) fit = garchFit(~ arma(1,0)+garch(1,1), data = y,include.mean=FALSE) summary(fit)
please see here (page 11) for more details
This would get you started. I would suggest reading some time series books (ex. Ruey S Tsay) for a better grasp of subject.