Welkom on the ‘How to Get Started’ page of Lavaan. This page might have changed since you last visited. The tutorial on how to run a simple regression model in Lavaan can now be found here. We also have tutorials on how to run the same model, but in a Bayesian way, in Blavaan here, if you want to use Jags and here, if you want to use Stan.
For more, really a lot more, of information on how to use Lavaan please refer to this CRAN website.