To install the Zoho Books app in your Freshdesk helpdesk, follow these simple steps:

1. Login to your support portal as an administrator.
2. Go to Admin > Apps. 
3. Click on "Get More Apps" and select Zoho Books.
4. Click on Install. You will be asked for Zoho Books API KEY.
5.  Enter it and click on Install to integrate Zoho Books with Freshdesk.