Flea

I have been following a project on git hub and none of the commands work like the project as I have Armbian Focal installed. I need Armbian Bionic with Linux opiz2b 4.19.57-sunxi #5.90 SMP or 4.19.127-sunxi. I realise this is from 2019 and may be too old now to do anything with it. Is it possible to still get this? I can only find minimal versions in the archives that are much newer than this. I have to state here that I am a complete novice at this and so really have no idea what I am doing.