Added shape of clm array

docs/user-guide/gravitational-harmonics/index.rst

@@ -85,7 +85,13 @@ Now the user can set up the rest of the simulation as usual. ::
 Manually Adding the Coefficients
 ================================
 
-If the user already has the coefficients, they can be added to the central body directly. Ensure that they are correctly normalized. ::
+If the user already has the coefficients, they can be added to the central body directly. Ensure that they are correctly normalized and 
+the right shape. The dimensions of `c_lm` is `[sign, l, m]` where: 
+- `sign` indicates coefficients of positive (`[0]`) and negative (`[1]`) `m` and is of length 2. 
+- The dimension `l` corresponds to the degree of the Spherical Harmonic and is of length :math:`l_{max} + 1`.
+- The dimension `m` corresponds to the order of the Spherical Harmonic and is of length :math:`l_{max} + 1`.
+
+:math:`l_{max}` is the highest order of the coefficients. ::
 
     c_lm = ..... # defined by the user
     sim.add_body(name = 'Body', mass = cb_mass, rot = cb_rot, radius = cb_radius, c_lm = c_lm)