What to consider when designing an end-to-end environment for a new company?

So I’m still an undergrad student who’s majored in Networking. In couple months I’m gonna start my internship and there’s this IT consultant who works for the company I’m gonna work for asked me if I’d know how to design an end-to-end environment had I been asked to. I think it’s kind of interesting since I’ve never done it before, and wanted to know any considerations a beginner like me should take before trying a task like that. Any comments would be appreciated.

Thanks!