There are plenty of places on the web to receive information about minhagei haGra, As has been correctly pointed out,there is tremendous variability in which minhagim are kept where, and to what extent.Almost all people who say they follow the Gra do not follow him to the absolute degree.
As an example, I know of no shul in Chutz La’aretz, and a very few here in Israel, that follow the Gra’s chalukat aliyot on Rosh Hodesh. Tukochinsky’s luach has this minhag as the proper way to lein, but almost no one does it.