This R tutorial automates the BCH two-step axiliary variable procedure (Bolk, Croon, Hagenaars, 2004) using the MplusAutomation package (Hallquist & Wiley, 2018) to estimate models and extract relevant parameters. To learn more about auxiliary variable integration methods and why multi-step methods are necessary for producing un-biased estimates see Asparouhov & Muthén (2014). The name of this mehtod, BCH, stands for Bolck, Croon, & Hagenaars, the authors who developed this method (Bolk, Croon, Hagenaars, 2004). This tutorial utilizes the public-use data repository named the Longitudinal Survey of American Youth (LSAY; Miller et al., 1992). The applied example used in this tutorial is based off the example presented in the seminal chapter on mixture modeling by Katherine Masyn (2013). This tutorial contains the 9 math indicators from this original study as well as two auxiliary variables.