Ferrules require a special crimping tool if you are not aware.I have a crimper but no ferrules
Crimping Tool Set, HCYW Self-Adjustable Ratchet Bootlace Wire Crimping Tool (AWG 23-7), 0.25-10mm² Ferrule Crimping Tool Kit with 1200 Wire End Ferrule Connectors https://www.amazon.co.uk/dp/B0CNR84K8V?tag=mhf04-21