First create your ShareProgress page, then create a redirect page in Nationbuilder.
1. Create Your ShareProgress Page
After you create a page on ShareProgress, you will receive a URL for your newly-created share page. Highlight this URL and copy it on to your clipboard.
2. Create a Nationbuilder Redirect Slug
With your ShareProgress share page copied, log into your Nation and create a new "Redirect" page. Nationbuilder has many different options for pages, the redirect option will look like this:
Paste your ShareProgress URL as the redirect URL and save your redirect page. Copy your slug for the final step.
3. Add your redirect to your Nationbuilder Petition
Find your petition on Nationbuilder and click on the "Petition Settings" tab and then click on the "Basics" subtab.
When prompted "After signing, what page should they land on next?", select the redirect slug you created in step 2.