Design thinking is a popular topic in product development and UX and is above all a mindset. But what you probably most often see is the design thinking process whereas one of the most known is the Stanford design thinking process consisting of five steps or modes: Empathize, Define, Ideate, Prototype and Test. It is an iterative and non-linear process where you can go back and forth between the steps. Here is a short description:
Observe, engage, watch and listen to understand people within the context you are looking at. Try to understand the way they think, why they do things and what is meaningful to them.
Analyse the information gathered in the Empathize step. What do the user’s needs look like? Collect insights and describe them as actionable problem statements.
Generate different ideas by brainstorming, creating mind maps, sketching etc.
Do prototypes on the different ideas. A prototype can be as simple as a non-interactive wireframe or a more advanced interactive one, with or without design elements. Start simple and iterate based on what you learn in the next step.
Let users test the prototypes and ask them what they think about the different ones. Iterate when needed.
5 Stages in the Design Thinking Process, https://www.interaction-design.org/literature/article/5-stages-in-the-design-thinking-process
An Introduction to Design Thinking Process Guide, https://web.stanford.edu/~mshanks/MichaelShanks/files/509554.pdf