You can use a ‘target’ URL parameter to set which tab will be open when the page initially loads. The value of this parameter is based on the tab title specified in the tabby shortcode, but formatted with punctuation & special characters removed and with dashes replacing the spaces.
If you want to link to a ‘contacts’ page with a tab titled ‘Phone Numbers’ open, the url you use to link to this page would look like:
https://yoursite.com/contact/?target=phone-numbers
If you want a tab with the title ’email addresses’ to be open, the url would look like:
https://yoursite.com/contact/?target=email-addressess
As an added option, if you also want the tabgroup to be shown as if it has already been scrolled into position you can also specify the anchor of one of the tabs in the tabgroup:
https://yoursite.com/contact/?target=email-addressess#tablist1-tab1
