This is commonly referred to as the Stable Diffusion paper since it was published with Stability AI's initial models and algorithm for Stable Diffusion.
Some nice Google Colab workbooks that let you run Stable Diffusion for free can be found on this page for "Stable Diffusion in TensorFlow / Keras". Try this notebook, if you aren't sure where to start.
These are some helpful links related to this paper, the algorithm and improvements since publication.