You say that you are trying to install Lion (Sierra) from the Internet.
Lion (10.7) and Sierra (10.12) are two totally different versions of the OS and are a long way apart.
Where, exactly, are you trying to download these things from, and which one is it that you are trying to install?
I have a 2012 macbook. Its original HD went down recently.
I'm trying to use a brand new 1 TB HD from West Digital. I can't install Lion (Sierra) OS from the internet (pen drive) on it. I've got "signature" or "can't download elements" errors at the end of the installation.
Any tips or suggestions to solve that?
Thanks a bunch!!