I am working with soft tab in appgyver for my app

I am working with soft tab in appgyver for my app, but unfourtuaelty i am not able to figure out where i am going wrong .

i am referring this link Soft tabs - Composer

Please help me with a video explaining how to use the soft tab for my app

Particularly this section

Showing active tab

Next, we want to make the cell bottom border color be dynamic based on the selected tab.

For each of the three cells, set border style to solid , bottom border width to 2 . Then, we’ll make the border color dynamic with the formula:

IF(pageVars.selectedTab === "info", theme.$colorNotice, theme.$colorContentSubdued)

The condition will be different for each of the tabs – pageVars.selectedTab === "log" and pageVars.selectedTab == "attachments" , respectively.

Since we set the default value to be info , the first tab should be selected when we preview our app.

The first tab is selected.