Ungoogled Chromium on Pinephone

[mlnease]

Hello,

I'd like to install Ungoogled Chromium on my Manjaro Arm Phosh Pinephone.  I don't see it as an option in Pamac and have read elsewhere that downloading software risks fatal partial upgrades (as I understand it). 

Can anyone advise me as to how to safely add the repository to Pamac or otherwise safely install this application?

Thanks in advance.

mn