Electric field vector tangent to the field lines at every point. Number of field lines per unit area is proportional to the electric field strength. Field lines never cross. You should know how to draw electric field lines. PE zero at infinite separation.
PE is the total energy stored in the charge configuration.
PE negative means it takes negative work to push the charges together. PE positive means it takes positive work to push the charges together. Electric Potential is a scalar. Capacitance is the ability to store charge.