First, create all your guiding documents!
• Values Statement
• Mission Statement
• Cultural Statement
• Vision Statement
• Experiential Goal Statement (the overarching experience you want people to have whenever they have a touch point with any aspect of your company)

That’s regarding your entire company.

Then, for a specific product (in your case, a piece of content) you want to define:
• What Experience do I want to create and who is that designed for?
• What Benefit(s) do I want those people to gain from that Experience?
• Why would those people find this Valuable and what value are they likely to derive from it?

Your brand starts with defining these things.
You create your brand around these things.

Your brand is only as strong as it authentically represents these things, delivers on these things, and aligns these things with people in the marketplace in order to build a community that shares in these things.