You can change the publication date of a blog post before or after it's published. This changes the order in which posts appear on a Blog Page.
Note: To schedule blog posts in advance, visit Scheduling blog posts. To learn more about adding a Blog Page, visit Blogging with Squarespace.
Step 1 - Open the Blog Page
In the Home Menu, click Pages, then click the Blog Page with the post you'd like to adjust.
Step 2 - Open the post
Click the blog post you'd like to change. Click Edit to open the Post Editor.
Step 3 - Change the date
In the Post Editor, click the current publication date below Published.
Select a new date and time from calendar that opens.
Click on the post content to close the calendar, and then click Save. You'll now see the post's new publication date on your Blog Page.