Anarchist (ancap anyway) principles boil down to individuals, not societies. If you're minding your own business, not aggressing, you're doing the thing. If others are interacting with you on those terms and nobody is aggressing, great, you're all doing the thing. If someone or some group moves in and starts aggressing, you defend yourself/ves.
Being willing to forego consumption to invest in defenses is crucial in the presence of would be attackers. There's a lot of ways you may approach this, but as long as it's voluntary the 'best' way is likely a matter of empirical trial and error.
It could look feudalistic, where a large land owner agrees to provide access to land to farmers in exchange for produce, and incentivizes the deal through offering that food to defense forces.
Or it could look more horizontal where a bunch of farmers each either maintain their own defenses and collaborate with their neighbors, or who perhaps hire defense forces.
Which methods make sense always depend on what you're defending against.
Fwiw I don't think everyone who'd call themselves anarchist would view the feudal model as I depicted it is indeed anarchistic, even though it is in line with libertarian nonaggression (as it's clearly hierarchic, rather than anarchic). So it does start getting into some semantic grey areas quickly.
