Teaching a weanling to lead correctly is one of the most important foundational skills in its entire training career, and the quality of that early lead training will be felt every time the horse is handled for the next twenty or thirty years. A horse that leads well — that walks off when asked, stops when asked, maintains appropriate space from the handler, and does not barge, pull back, or plant — is safe to handle and easy to work with in every subsequent context.
The foundation of leading is pressure and release — the foal learns that light pressure on the halter means move forward and that moving forward immediately produces the release of that pressure. This is taught by applying gentle forward pressure on the lead rope and the instant the foal takes even one step forward, releasing completely and allowing the foal to stand. The foal quickly learns that forward movement is the release from pressure and begins to walk off with progressively lighter cues.
The critical mistake most people make with weanlings is pulling. Pulling a weanling forward produces a pull-back response — the foal braces and pulls backward against the pressure, which is the exact opposite of what leading requires. Leading teaching is always about drawing the foal forward with the lightest possible pressure and releasing the instant any try is offered, never about overpowering the foal's brace.
Once the forward response is reliable, the stop is taught by bringing steady light backward pressure on the lead rope and releasing the moment the foal's feet stop. Turns, backing, and tying all build on this same pressure-release foundation. A weanling that is leading well within its first few sessions — walking off when asked, stopping softly, turning both directions — has the groundwork vocabulary that will serve every trainer that ever works with it.