If Main Page redirect is not specified – you can use a Main Page feature on your main domain, for creating a link-in-bio or smart-link like page.
To access it, proceed to Main Page tab:
Here is the example of completed Main Page:
Let's breakdown the main features:
1) To set up the background image, click on the highlighted button > Choose background
2) To add a short link to the page, specify only a slug of existing short link.
For example: if short links is domain.com/buick - specify just buick, and click Add.
3) To change the arrangement of links - click the highlighted icon and drag to desired position.
After editing is done, click Save Changes.