There're at least two/three rounds of interviews:
The first was a chat with the cofounder, discussing about this opportunity briefly, including a self introduction.
The second was a take-home task for training a model in a binary semantic segmentation for rails. (1 week to finish, +slides)
The third was a real interview with a ML engineer. Deliver the presentation for the take-home task + some questions + brief introductions for their projects.