How do play as Sejuani?

I'm Plat so I assume I have basic knowledge to learn any champion quickly to a decent extent. However, after numerous trials of Sejuani in either TOP or JG, I often found myself feeding or irrelevant to the game. I checked many builds on the internet, still failed every time.

I want to play her so much for her PORO skin. Please can anyone tell me how to excel as her?