You can Download Classy integration guide Here.
You can view the steps to integrate below as well:
Step 1) On the Integration page, click "Install" in the Classy box. We required four fields from Classy: Client_id, Client_secret, Org_id, and Campaign_name.
For the next steps, you will need to log into your Classy account.
Step 2) Create a new Classy campaign and name is "Online Auction". When filling in the Campaign Name field on CharityAuctionsToday, enter "Online Auction", the exact same way you named the campaign.
Step 3) On classy account there is API section were we need to create new API so we can pull the client ID and Client Secret.
Step 4) The last step if finding the Org ID. You can find this in the address bar when you are logged into your Classy dashboard. See screen shot below.
In the top right corner, click on the profile photo icon. Next click on Organization_Dashboard. Once the page loads, in the Url you will see the Org_id which we need to put that in our Org_id input field on CharityAuctionsToday.
Download integration guide here.