By default, when you open a Project, Inspire Planner takes you to the Inspire Planner Project User Interface. However, you can create your own custom lightning project page and configure Inspire Planner to default to your page when viewing projects. This help article will show you how.
First, you will need to create your custom Lightning Project page. To learn more about Lightning pages, see Salesforce: Lightning Pages.
Once you've created a custom Lightning Project page, you would need to enable a custom setting within Inspire Planner to use it.