The NHL preseason started on September 21st. The 2024 preseason goes until early October, and the regular season goes from early October until early April.
The Preseason for the NHL is when all teams play unrecorded, also called an exhibition. These games go on for about two weeks. Some teams playing this week are the Dallas Stars, The Oilers, the Tampa Bay Lighting, the NY Rangers, the Florida Panthers, the Penguins, and the Bruins. The entire point of the preseason is basically for coaches to evaluate their teams, change the rosters, allow the players to try different positions, etc.
Some of the places you can watch these preseason games are ESPN+, Regional Sports Network (RSN), and NHL Network.