To edit an existing helper, head to the "helpers" page (in your left menu) and click on the edit icon for the helper that you'd like to update.

A panel should appear that shows the current settings for this helper.

Make any updates that you'd like, and hit save. Easy.

Alternatively, you can launch the visualizer tool on a page that you know the helper is loaded on, click on "edit contextuals", find the helper that you want to change, and click edit. Make the changes you want, and hit save.