1.There is an app for Chrome Remote Desktop you'll download on the PC/MAC you want to access. Link here: https://chrome.google.com/webstore/detail/chrome-remote-desktop/gbchcmhmhahfdphkhkmpfmihenigjmpp
2. Once it downloads it will ask if you are accessing your personal computer or a remote assistance computer.
-If you connect as Remote Assistance it will be a one time connection with a random string of 12 digits.
-If you choose a personal computer it will ask you to create a 6 digit pin that will allow remote access to that computer as many times as you want.
3.Then on your chromebook you will open the remote desktop app and choose however you are connecting (either the 6 digit pin or 12 digit unique code). It will then connect and you'll be able to access your pc from your chromebook.
NOTE: This is a one way process. You will not be able to access your chromebook from your other PC.