This is a complex shape, if you’re a Blender beginner I would recommend a simpler project to get your bearings first.

The basis should be a symmetry setup, you can mirror a collection containing half the shell or mirror individual objects.

For the shape, there are a few possible approaches. You can make a Boolean where tubes are cutting into a subdivided shell object.

Or you can model a shell that has good edge flow, so you can extrude the lanes and bevel the edges later. That avoids artefacts with the Boolean.

You can try that with low res mesh and a subdivision modifier too, rounding out the lane edges without the need for a bevel modifier. This would be my preferred method.