I started by trying to understand what the core problems were for both the business and the end users. This included mapping out the current user journeys using simple stories to help highlight the pain points. I also spent some time mapping out basic journeys for each mode of transport I could think of to find patterns with the aim to create a simple, consistent flow for a multi modal solution that would require minimal tuition to use.
Once a suitable flow was established I then needed to work with the client and the development team to prioritise features based on effort and value. Once a feature set and user flow was agreed upon I was able to start fleshing out some ideas on the visuals, seeking feedback regularly to avoid technical constraints.