How do I create a Blog Page on Genesis?

Navigate to Pages > Add New. 
Give your new page a name of Blog, Journal, or something similar.
On the right under Page Attributes, you'll see a Template dropdown. You'll select Blog Page from that drop down.

NOTE: If the Blog Page Template is not available, select "default" and continue with the tutorial.

Set a Custom Field

Click the 3 vertical dots in the top right of your screen and from that drop down, select Preferences at the bottom.

WordPress v.5.6.2 (see below for v.5.7)

From the panel that pops up, be sure Custom Fields has a checkmark next to it.

If it brings up a message to Enable + Reload, go ahead and click that

On the left side, under the post content, scroll down until you see the Custom Fields section.
Select the Enter new Option.
Enter query_args in the name field.
Enter showposts=6 in the value field.

Publish your page. Now all your blog posts are on the blog page!

For more information about how to use query_args, see this article by Studiopress that shows how you can include/exclude specific categories.

WordPress 5.7

From the screen that pops up, select "Panels" on the left, then turn on "Custom Fields."


If it brings up a message to Enable + Reload, go ahead and click that

On the left side, under the post content, scroll down until you see the Custom Fields section.
Select the Enter new Option.
Enter query_args in the name field.
Enter showposts=6 in the value field.

Publish your page. Now all your blog posts are on the blog page!

For more information about how to use query_args, see this article by Studiopress that shows how you can include/exclude specific categories.