You can’t create a button on the left that leads directly to an external webpage. However as you suggest it is possible to create an automatic redirect.
First you need to create a new blank page using Step 3 Webpages. The place the button within the buttons on the left. This can be done in Step 3 Webpages, Organising pages.
Once you’ve added the page go to edit it. Then click “Show HTML” in the editing bar on the page.
The code you need to enter is:
In the highlighted portion that currently says Website Builder | Build a Website | Create an ecommerce business | Reason8
, replace it with the full address of the page you want the user to be directed to. Ensuring when you do that you preserve the quotation marks o either side.
Once saved the page will redirect immediately.
To create a blog on your site
you can either use your webpages (noting that they are not infinite). Or you can use an external blog provider and either link to the page using text or create a window on your site
so users can see the blog while still on your website. (I can provide you more information on this is you would like to explore the option).
We hope this is helpful,