[embedder] Updating documentation to instruct user to set the target device to the fuchsia-emulator in ffx. This will make sure commands like ffx log, ffx target <subcommand>, etc. know which device to connect to.

Change-Id: I713edaa04c8843a44e27c02aa0732b311b6ba158
diff --git a/README.md b/README.md
index debc90a..d8f7d49 100644
--- a/README.md
+++ b/README.md
@@ -41,8 +41,14 @@
    $FUCHSIA_EMBEDDER_DIR/tools/ffx emu start --headless workstation_eng.qemu-x64
+2. Set the default target in ffx to be `fuchsia-emulator`:
+   ```sh
+   $FUCHSIA_EMBEDDER_DIR/tools/ffx target default set fuchsia-emulator
+   ```
 3. (optional) Watch the device log in a separate window: