The WooCommerce Payment Plans plugin is compatible with LearnDash courses and LearnDash Groups. But, when applying it to LearnDash courses, you need to apply it as a Simple product instead of as a Course.

Here are the steps for applying the WooCommerce Payment Plans plugin to a LearnDash course:

1. Create a new WooCommerce product in WordPress.
2. Select Simple product from the Product data dropdown box.
3. Check the Virtual checkbox.
4. Add the price of the course.
5. Select the course(s) that you want to offer.
6. Click the Payment Plans tab.
7. Configure your payment plan options.
8. Save and publish your product.

In the following example, I have set up a Learn Guitar Course that I am selling for $100 or 4 monthly payments of $25:

To properly apply the plugin to a LearnDash course, you also have to change some LearnDash settings. Go to LearnDash LMS > Courses and update the course’s settings to Closed Access Mode and set the Button URL to either your cart or product page, like this:

Finally, do the following steps to prevent LearnDash from removing a user from a course after they complete all their payments:

• On your WordPress dashboard, go to  WooCommerce > Settings > and click the Subscriptions tab.
• Next, scroll down to the bottom of the Subscriptions settings and check the  Disable checkbox under Access Removal on Expiration.

Next, click Save changes.