Do some study on Rausas John Rushdoony who these guys all follow and understand his teaching on Dominionism and having to establish a theocracy world wide with all the laws of Old Testament Israel in place before Christ can return to see how off the wall and anti scripture they really are.
Just going from memory here, but I believe Rusdooney would hold to sola scriptura
And I will venture a guess that he claims that he is led by the Holy Spirit.