This guide first reviews the Ranada field line solutions of Maxwell's equations in a vacuum, describing a topologically non-trivial electromagnetic field, as well as their relation with the knot theory. Also, the authors present a generalisation of these solutions to the non-linear electrodynamics recently published in the literature. Next, this compilation reviews the gravitating electromagnetic field in the 1+3 formalism on a general hyperbolic space-time manifold, discussing the recent results regarding the existence of local field line solutions to the Einstein-Maxwell equations. Lastly, the authors consider the existence of a weak solution to a class of an evolutionary Maxwell-Stokes type problem containing a p-curlcurl system in a multi-connected domain.