If you have created more than one line under a given campaign, you can switch between lines by clicking the line name and choosing a ‘sibling’ line. You can switch to a different line from any of the following line sub-tabs (Insights, Ads, Targeting, Bid Multipliers, Line Properties).
To select a different line in the same campaign:
Click on the drop-down arrow next to the line name.
Select from the displayed list or filter the displayed list based on text or line ID.
Select the line you want to work with.
In the list of lines on the dropdown menu, the current line is highlighted in bold.