Seeking ee.Classifier.smileRandomForest() explanation

Random Forest is a machine learning algorithm and like every other algorithm, it has some hyperparameters. 10 is the no. of decision trees that Random Forest will use to make a prediction.

Every decision tree will give its output for the data you pass and based on the decision of those trees your classifier will produce its prediction. It all happens internally so you don't have to worry about the algo itself.

Just try to play with this no. to find which suits your data best.