Getting an API key
Before you can do anything with Freesound, you'll need an API key.
Get a Freesound account. It's free. Go to www.freesound.org and sign up.
After you've logged in go to https://freesound.org/apiv2/apply/
Fill in the form to apply for a new set of API keys.
You may notice that Freesound has fewer keys than Twitter. That's because Freesound only hands out client keys, not access keys. So, whereas using the access keys someone could post tweets from your Twitter account, the same isn't true for Freesound.
Anyway, note down the client ID and API key.
In this freesound folder, you should see a file named .env-template. This is an environment file, it contains key-value pairs that other applications, like Node, can load before running.
Duplicate the .env-template file to a new file named .env. It must be named .env, not my.env or anything like that. Fill in this file using the keys you got from Freesound.
You should be all set. Open the Max patcher freesound.maxpat and see!