Here is the general formula for the z-matrix you can use in jaguar
Atom1
Atom2 Atom1 D1
Atom3 Atom2 D2 Atom1 Angle1
Atom4 Atom3 D3 Atom2 Angle2 Atom1 Dihedral1
etc
D1 = Distance between atoms 1 and 2
D2 = Distance between atoms 2 and 3
D3 = Distance between atoms 3 and 4
Angle1 = Angle between atoms 1, 2, and 3
Dihedral1 = Dihedral between atoms 1, 2, 3, and 4
An example of a completed z-matrix
Ti1
X Ti1 1.32
Ti4 X 1.9995355167 Ti1 89.9999880141
Ti2 X 1.32 Ti4 89.9999880141 Ti1 -179.9999760486
Ti3 X 1.9995355167 Ti4 105.000000000 Ti2 89.9999880141
For this structure, X is a "dummy" atom