If your Prestashop page uses Ap BageBuilder to insert content on the home page, Clerk recommendations on the home page must be inserted through this plugin.
Simply go to Ap PageBuilder in the menu to the left in your Prestashop backend and click Ap Profiles Manage:
You will then be sent to an editor of the home page. Click Edit on the element in which you want to insert Clerk recommendations. Insert the embed code of the Clerk recommendation you wish to insert by using a RawHTML container:
Press Save. You're Clerk elements should now load on the front page (you might have to clear your cache first though).