1. Enable Play Store
When logging in for the first time, you will get prompt in the bottom right corner to sign in to the Play store. You can also open it from the start menu in the bottom left corner.
Once in Google Play store,
2. Download Microsoft Remote Desktop app
3. Install the app to your Chromebook
4. Download your rdp file from https://myrdp.download/
5. Connect to the could desktop
After downloading the file, right click it and select "Open with"
Then select RD Client
Click Allow on the first pop up, then you'll get the connections screen. Click CONNECT
Your User name will already be populated, just click CONNECT again and you will be connected to the cloud desktop.
Note: there are also third party clients such as XtraLogic that provide good experience connecting to a remote desktops from a Chrome device when using multiple monitors or docking stations.