A "user journey" is a series of steps which represent a scenario in which someone might interact with the thing you are designing.
It demonstrates the path users will take through the tool to accomplish their end-goal.
"If you have a good idea, don't tell anyone... tell everyone."
- Muriel Cooper
It doesn't matter if its on the back of a napkin, a scribble on a whiteboard, or a poorly design PowerPoint presentation, all ideas needs to start somewhere.
Plan. Talk. Discuss. Communicate.
Get the idea out there so others can see why its important, and become excited about it too. The more others understand, the easier it will be for them to become excited about using what your building.
Show them what BOTH the "forest" and the "trees" look like.
Let them see your idea from 30,000 feet, as well as being on the ground "in the weeds."
Build it! It doesn't have to be perfect the first time. Get it out there, and listen.
Listen to your user's feedback.
And then get back to the drawing board, because there's still more fun to be had!