I looked it up but couldn't come up with some explanation that I felt comfortable with.
"Einführen" means introducing something into a context, where it wasn't present or known before. Either physically (putting a key into a lock) or as concept (introducing an idea into a discussion).
"Gründen" means creating/founding something that did not exist before. Either physically (building) or as a concept (company).
The words also give you a significant hint on the inherent meaning: "Einführen" consists of the words "Ein" (into) and "führen" (lead). Which is why i used Intro-Duce (~lead into) as a translation.
"Gründen" is the verbalized form of the noun "Grund" (~foundation or ~reason).