Personal branding for a tech founder

I have a client who is currently working on a tech company but its not yet public and before his company went public he wants to build a personal brand.

I am the strategiest and I have to create him a content plan and strategy but the restrictions and dos and donts are too much also the audience is not clear that it make me overwhelmed and currently I am feeling stuck i mean cant find a way to get start.

Any social media strategiest here I need some help with clarity