Update

docs/userguide/lr.md

@@ -245,8 +245,18 @@ This output feature file resembles the one generated by the `simulate` subcomman
 
 ## `train`
 
+Once the training data is created using the `simulate` subcommand, users can use the `train` subcommand to train a logsitic regression model.
+
 ### Example
 
+An example command is below:
+
+```
+gaia lr train --training-data examples/results/data/training/examples.features --model-file examples/results/trained_model/example.lr.model --seed 12345
+```
+
+The trained model, which is a binary file, can be found [here](https://github.com/xin-huang/gaia/blob/dev/examples/results/trained_model/example.lr.model).
+
 ### Arguments
 
 | Argument | Description |
@@ -261,8 +271,21 @@ This output feature file resembles the one generated by the `simulate` subcomman
 
 ## `infer`
 
+Once a trained model is obtained, users can utilize the `infer` subcommand to make predicitions on the features processed by the `preprocess` subcommand.
+
 ### Example
 
+An example command is below:
+
+```
+gaia lr infer --inference-data examples/results/data/test/example.lr.features --model-file examples/results/trained_model/example.lr.model --output-file examples/results/inference/example.lr.predictions
+```
+
+The predictions are available [here](https://github.com/xin-huang/gaia/blob/dev/examples/results/inference/example.lr.predictions) and appears as follows:
+
+```
+```
+
 ### Arguments
 
 | Argument | Description |