Not sure if this is the original intent, but I personally see it as not requiring individuals to work a standard work week to survive. None of this nuance is here so I can't say for sure, but those wanting a minimal life can spend time on skills development, personal endeavours, teaching, volunteering*, occasional gig work, or just vibing with little and being content with getting by.
Those who want more than getting by, which I can only speculate is a lot of people, and those driven to work, can work. The value proposition of work would change drastically, though, as value for types of labour change drastically.
Right now, many of the most well paid jobs are the cushiest. People want them not just because they are the highest paid with best benefits, but because they are low physical labour, flexible, "clean". Meanwhile the jobs people argue nobody would do - customer service, waste management, line work (which very well might be mostly replaced with automation in the next 20 years) - the incentive would need to be way higher because now you aren't working it to live, you're working it to live better.
I know it isn't apples to apples by any stretch, but some of the biggest software used today was made by volunteers working alongside their jobs. A huge part of university teaching is done by contractors with terrible wages and precarious conditions because they just love teaching (and of course other pretty awful reasons for many).
A combination of flipping to worker owned co-operatives to minimize administrative/BS-job waste and give labourers ownership over their labour to keep them invested, alongside a minimum income and regulations to flip wages so that the less desirable the job, the higher the financial incentive, forcing companies to actually cut waste and reduce excess production because labour won't be as ubiquitous, firm regulations to prevent mass wealth accumulation and ensure fair wealth distribution among labourers and allocate funds to industries that meet basic human needs, and embracing automation rather than rejecting it to make up the labour shortage.
All this said - I have no idea if this will work out positively, highly doubtful it could happen at a large scale, recognize there is likely 1000 holes here and new problems to arise, and don't fully believe it's feasible nor that I'm remotely intelligent enough to claim this has any real grounding. Speculative, hopeful, a worthwhile thought experiment to mine for ideas, a place to avoid black-and-white thinking on issues like a 0 hour workweek.
Edit: oh yeah, I asterisked volunteering because many of the volunteer efforts we have now are really extremely valuable for survival and I can't imagine what we see as volunteering now would still be freely provided labour, but I have no ideas what industries would and wouldn't be volunteer driven (I mean, we likely didn't anticipate the biggest and most ubiquitous software projects being entirely volunteer based)
I'm a professor so I caveat quite a bit when I'm outside my domain out of habit, I appreciate the notes here and definitely see how folks could come in with highly skewed perspectives against what's possible or what's meant there. The terms here help, thank you!