Install app for client with collaborator account

[daveh0]

I have a Shopify partner account that I use to access my client's live store (as a Collaborator account). I am trying to install the Google Channel app for them. I can make it to this page: https://apps.shopify.com/google?auth=1&surface_detail=google%20channel&surface_inter_position=1&surf..., but when  click 'Add App', a modal window is displayed asking me to log into the store directly.

and since I don't have a staff account I am not able to log directly into the store (via my-clients-shop.myshopoify.com). Am I missing something or do I need a staff account in order to install this app?