The current OEM installer (eg. https://downloads.puri.sm/oem/gnome/2018-04-26/pureos-8.0-gnome-oem_20180426-amd64.hybrid.iso) goes through the initial keyboard/wifi setup etc., then ends with a "Start using PureOS" button that looks final as it is differently coloured.

However, this should (at least) not say "using" as you are then taken to the partitioner - you aren't using it yet. My suggestion is "Continue installing PureOS".