Covariant derivative along a curve

See @lee2006riemannian Lemma 4.9.
How can we derive vector fields defined on a curve, with respect to the parameter of the curve?

Given a covariant derivative operator ∇ in a manifold M, for each curve γ:I→M, ∇ determines a unique operator

Dt:T(γ)→T(γ)

satisfying the following properties:
(a) Linearity over R:

Dt(aV+bW)=aDtV+bDtWfor a,b∈R.

(b) Product rule:

Dt(fV)=f˙V+fDtVfor f∈C∞(I).

(c) If V is extendible, then for any extension V~ of V,

DtV(t)=∇γ˙(t)V~.

For any V∈T(γ), DtV is called the covariant derivative of V along γ.

Local coordinate expression

DtV(t0)=V˙i(t0)∂i+Vi(t0)∇γ˙(t0)∂i=(V˙k(t0)+Vi(t0)γ˙j(t0)Γijk(γ(t0)))∂k.