A Collection of Data and Links to get you started! (I stole this from reddit)
Core Rules Read Thru (by u/GlassHalfDeadTV):
https://www.youtube.com/watch?v=7JKT2i3VFyo
Core Rules Sneak Peek (Thanks /u/subaqueousReach): https://drive.google.com/drive/u/0/folders/1Uu3nGpBCOGtCLL7Vh_jIac99Yy4s9rEF
Rules Overview (CanYouRollACrit):
https://canyourollacrit.com/2021/08/09/kill-team-octarius/
Free Online “Course” for Learning the Rules (by u/emilbrett ):
https://rise.articulate.com/share/YnYJx_m1yFjcjdtI7befC35yuEABqa-T#/
How to Play Kill Team (Part 1) (from Strategic Advantage): https://www.youtube.com/watch?v=Ju1kuzrtje0
Line-of-Sight, Cover, and Order Rules Explained (by u/GlassHalfDeadTV):
https://www.youtube.com/watch?v=t4wmh_rxBwA
Easy To Miss Rules List & Discussion
https://www.reddit.com/r/killteam/comments/pkbzib/easy_to_miss_rules/
Compendium Sneak Peek (Thanks /u/subaqueousReach):
https://drive.google.com/drive/u/0/folders/1EbzBrGbMiW9KGZPgCzmmyrTKXJDg4BSo
THE KT 21 Reference Sheet PDF (by u/ChronoDK):
https://drive.google.com/file/d/1kgToAvu_TXRmAQIA1kkdLKih4rCJOE6u/view
KT21 Single Sheet Reference/Rules (by u/Armagonix):
https://www.dropbox.com/s/mrtt6z924u1h3lt/kt2_rules.pdf?dl=0
FAQs about the rules explained by a normal person (by u/JeremiahBlitz):
https://www.offmetamusings.com/2021/09/killteam-2021-frequently-asked-questions.html
One-Box Kill Teams for Beginners ( u/GlassHalfDeadTV): https://www.youtube.com/watch?v=waXbxVdwRow
Top 5 Kill Teams for Beginners ( u/GlassHalfDeadTV): https://www.youtube.com/watch?v=zJ_oNPAFCMs
Kill Team Models, Weapons, and Damage spreadsheet (by u/OriginalUsernameX):
https://docs.google.com/spreadsheets/d/1Sa76-kNCVpLe0sLMEryo7l7QdZZOBqOrkhnENj55Mtc/edit#gid=0
Kill Team Costs Spreadsheet (by u/rogueguineapig):
How to setup your Terrain ( by u/GlassHalfDeadTV)https://youtu.be/MacG446wL6k
Many of these links helped me get a grip on the new system. What else should go on here