I am new to the API also, but I have located where to find my sandbox keys, CLIENT_ID and CLIENT_SECRET.
The first issue before being able to retrieve the keys on your dashboard is verifying your account.
Looking at your screenshot, it looks like your account is still unverified.
Verification requires just a bit of information input.
Next once you're verified and your status is green, you can click where it says "Go to Client Dashboard"
And You API keys can be seen when you click "show"
Sorry i had a ton of screenshots showing how to navigate, but I am prohibited from uploading more than 1 screen shot.