Update valet-forecast-lab.md

gitlab/valet-forecast-lab.md

@@ -1,7 +1,8 @@
 # Forecast the usage of a GitLab namespace
-## TBD
+In this lab we will us the `forecast` command to forecast potential GitHub Actions usage by computing metrics from historical pipeline data in the GitLab instance.  The metrics will be stored on disk in a markdown file and include job metrics for execution time, queue time, and concurrency.  We will look at each of these metrics in this lab.
 
 - [Prerequisites](#prerequisites)
+- [Prepare for forecast](#prepare-for-forecast)
 - [Perform a forecast](#perform-a-forecast)
 - [Review forecast output](#review-forecast-output)
 
@@ -10,6 +11,10 @@
 1. Followed [steps](../gitlab#readme) to set up your codespace environment.
 2. Completed the [configure lab](../gitlab/valet-configure-lab.md)
 
+## Prepare for forecast
+Before we can run the forecast we need to answer a few questions so we can construct the correct command
+1) What namespace do we want to run the forecast for?  __Valet__.
+2) What timeframe do we want to forecast?  
 
 ## Perform a forecast
 ### TBD