You collect information on who the users are and how they want to use the product.
Get to know about needs
Become familiar with different types of disability and how these influence the user experience. Try out different assisting technologies to understand how barriers can be overcome. Introduction to different disabilities: https://webaim.org/intro/#people
Include people with disabilities
As with all other users, you can of course also ask people with disabilities and invite them to take usability tests. This can be done via the SBB Disability Council or the various specialist working groups. Get in touch with your contacts.
Tips on user involvement: https://www.w3.org/WAI/test-evaluate/involving-users
Put yourself into the context
Don’t just sit in your familiar office; try to put yourself into the real situation. For example, try out how using the app with a Screen Reader feels when travelling somewhere.
Ideas for putting yourself into a different context: https://empathyprompts.net
Consider accessibility for your personas
Consider the different aspects of accessibility when compiling your personas and your user journeys.
Inspiration for personas: https://rosenfeldmedia.com/a-web-for-everyone/personas-for-accessible-ux