Researchers demystify ancient Aboriginal migration across Australia (2021)

We don't know whether they came via Sulawesi or Java, but both are Indonesian now. Both routes involved multiple substantial water crossings, even when sea levels were lowest.

They go into extensive detail of their methodology, but I'll give you a very brief summary that I think might explain why article says they 'take data' from all those folks.

1. Use environmental data to create layers which are superimposed onto the map and represent different concepts such as: water levels, creeks & rivers, topography, and terrain visibility (visual prominence).

2. Divide the map into a grid of 500sqm squares. Attribute these squares with value based on estimated caloric expenditure to traverse and the layer information created earlier.

3. Using a 25 year old woman as the agent, simulate the route of least caloric expenditure and plot it on the map.

(justification: Men travelled further, but often did so without families and thus are less suitable for migratory analysis)

So while strictly true from the ABC, the paper does take data from those sources, I totally agree with you calling that quote vague, its a very clickbaity interpretation of how data is used in the paper.