Support Forum

No - there is no shortcode - that's not how it works.

Simple:Press uses a standard WordPress page to display itself on. When installed it creates a page named 'Forum' with a page slug (for the url) 0f 'forum'. That page can then be added to any menu your WordPress theme creates via the WP pr theme customiser.

Within the WP Admin the new 'forum' page should have no content. Although if you DO add content it will be displayed above the forum which some users find useful to place static information.

You can change this page to any title and/or slug that you prefer. If you do this you will then also need to go to the forum admin > Integration > Page and Permalink panel and (1) Reselect the page being used if different. Update the page. And then (2) click on the 'Update Forum Permalink' button mid way down the form.

As I said on the original PM to you - page templates are a product of your theme. Most decent themes come packaged with a few templates and most commonly I would have expected a content + sidebar to be one of them. Load up the new forum page (or whatever page you decide to use) in WP 'Edit Page'.

Many themes will add a section to the page edit that slows you to select a layout. If not then WP itself will show a box named 'Page Attributes' which will allow you to choose the most appropriate template. (If you do  not see a page attributes section then it may be hidden - click on screen options at the top and then select the appropriate section).

At the end of the day, if there is no appropriate template to use for the display you need to discuss it with the authors of the theme but I would be surprised if this is the case.