The following command installs a recommended subset of the OpenCascade packages (and development headers) using apt. Since the packages are now available from the official repositories, you don’t need to add extra repositories.
sudo apt install -y xfonts-scalable libocct-data-exchange-dev libocct-draw-dev libocct-foundation-dev libocct-modeling-algorithms-dev libocct-modeling-data-dev libocct-ocaf-dev libocct-visualization-dev