Did it before just browsing apartment web sites and booking one for a few days. Not that hard.
The rest is book a flight, or drive, or Eurostar even (though the timetable is geared around weekends to make a week trip and maximum days skiing).
Flight/train would require booking a transfer also (though in any of the resorts near the train route you just pick up a bus from the station).
Package deals will be 7 days minimum, price per person with single person supplement charged on the whole price, and often crap flight times on a shitty charter flight, complete with long delays when things go wrong because they don’t have the resources to sort it out quickly like a proper airline can (from experience of the 14hr delay on last trip). Oh and the “transfer” which takes 2hrs longer than it should due to tonnes of faffing around and having to visit half a dozen other resorts to drop people off, and generally slow arse driving.