Ads on front page only?

Yes you can with condtional tags.
https://codex.www.ads-software.com/Conditional_Tags#The_Front_Page
It might look like this

<?php if (is_front_page()) { ?>
your ad code here
<?php } ; ?>

Thanks. Tried this, but the ad still shows up on the archive page.

Is the archive page set as the front page?

No, the front page is https://www.canucknation.ca, and the archive page is https://www.canucknation.ca/2008/08/

Thanks,
Rod

Did you happen to clear your cache in between putting the code in and checking the site. If not clear your browser cache and any wordpress caching you have then try again.

Just downloaded Opera and tried it, so I know it wasn’t in the cache. Unfortunately, the ad is still there.

Are you using a text widget to place the ad. If so php isn’t allowed in a text widget. You’ll either need to add it manually to the sidebar or use this plugin to create a widget that parses php.
https://www.ads-software.com/extend/plugins/php-code-widget/