In MM 2.2.3 and earlier the Thank You page is appended by /thankyou.php not /confirmation.
You may have a situation where you've created one or more free bundles and you want members to be able to select which one(s) they want applied to their account. If you want to allow a customer to apply a free bundle to their account just use the following link:
<a href="[MM_Member_Link type='freeBundle' value='10' redirectUrl='http://yourdomain.com/confirmation']">Accept this Free Gift</a>
NOTE: You will need to adjust the number in the value to be the correct bundle ID associated with your free bundle. You can locate this by hovering over the name of the bundle you would like in MemberMouse > Product Settings > Bundles. You can also adjust the messaging if you want it say something other than 'Accept this Free Gift'.
You can add this wherever you would like the link to appear on your website by going to Pages > All Pages > hover over the page name and click Edit > and clicking on the 'Text' tab
The result is that when a member clicks on this link, the free bundle with an ID of 10 will be automatically applied to their account and they'll be redirected to the Confirmation Core Page. The redirectUrl parameter is optional. If you don't provide this parameter the page will simply refresh following the bundle being applied to the member's account. Read this article to learn more about the MM_Member_Link SmartTag.