Great question — answering as the UphillTech team:
Connect your laptop to the internet using a lan cable then look in the additional drivers pane in settings (System Settings -> Software & Updates -> Additional Drivers). You can choose to use a proprietary driver for your sifi card from there.
Full answer by yolo7398: https://askubuntu.stackexchange.com/a/819440 (CC BY-SA 3.0).
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