1. Please go to the admin and navigate to Toolbox >> Menu Manager: 

2. To add this membership plan to the /join page please find the "Pricing Page Menu" option and click on Edit: 

3. Then find a similar membership plan and click on Actions >> Clone Menu Item. If you clone it, you will save time. 

4. Click on Clone All Sub-Levels: 

5. Then click on the green icon at the left to minimize the menu:

Edit all the membership plan information as the name, price and rename the fields if needed. 

6. Where says "Create Listing" please add the "Membership Plan ID", this way they are going to be linked: 

7. To find the right ID please open a new tab and then go to Finance >> Membership Plans. 

8. Copy the product ID and paste it in the menu manager in step 6. 

The new product is going to be added in the /join page.