1. First off, make sure you enabled them in the plugin Settings - > Subscriptions:
2. Second, navigate to Estatik plugin menu - > Subscriptions and create your first subscription plan by clicking on Create plan.
3. Fill in the fields in your plan form:
4. Save and Preview.
If you can see the table with Subscriptions, it means you've done everything correct:
To create another plan just click on 'Set up plan' which will navigate you to a new form:
The Page with Subscriptions shortcode will show all the plans created on the front-end.