This tutorial introduces MRStdLCRT, an R package for model-robust standardization in 2×2 crossover (CRXO) trials. We focus on two population-level estimands: i-ATE (individual-average treatment effect) and c-ATE (cluster-average treatment effect), and show how to obtain both unadjusted and adjusted estimates using LMM (lmer), GLMM (glmer), and GEE (gee). Uncertainty is quantified via delete-1 cluster jackknife standard errors, including for the difference (i-ATE - c-ATE)