add Utilities/README.md

Author: bkhouri

Utilities/README.md

@@ -1,11 +1,24 @@
 # Windows Self-Hosted Test
 
-Steps to be confirmed
+Here are some steps the worked running on Windows.
 
-```
-${REPO_ROOT_PATH} = git rev-parse --show-toplevel
-${TARGET_PATH} = "C:\source"
-
-docker pull swiftlang/swift:nightly-main-windowsservercore-1809
-docker run --rm --volume "${REPO_ROOT_PATH}:${TARGET_PATH}" --interactive --tty --name "win_test" --workdir "${TARGET_PATH}" swiftlang/swift:nightly-main-windowsservercore-1809 python3 .\Utilities\build-using-self
-```
+1. Install Docker on a Windows host
+2. Launch a `Powershell.exe` session
+3. Run the following in power shell to start a container running the nightly toolchain
+    ```
+    docker run --rm --interactive --tty swiftlang/swift:nightly-main-windowsservercore-1809 powershell.exe
+    ```
+4. When the container start, clone the "merged" PR to `C:\source`
+    ```
+    mkdir C:\source
+    cd C:\source
+    git clone https://github.com/swiftlang/swift-package-manager .
+    # Assign the PR ID to a variable
+    $PR_ID = "8288"
+    git fetch origin pull/$PR_ID/merge:ci_merge_$PR_ID
+    git checkout ci_merge_$PR_ID
+    ```
+5. Run the CI pipeline script
+    ```
+    python C:\source\Utilities\build-using-self
+    ```