Im trying to work out what rules still apply to white scars. I have watched lots of videos about the different space marine factions and white scars Play style appealed to me. Since getting the support codex I can't find the rule that lets them charge after falling back or advertising this being the main point of the videos I have watched as there are not very old I didn’t think it would be a redundant rule. So if anyone could shine some light on this rule it would be a great help.
James Otter's comment is right. The rule you're looking for the the Lightning Assault is the White Scar's "Chapter Tactic" and allows a Charge after Falling back or advancing.
It's covered in detail her Goonhamemr Review
Note that the linked articles are from the 8th Edition period, and Space Marines as GW's poster children are the most subject to frequent change. I'm unaware if these rules have been modified by the recent 9th Edition release.