Locating the filament pins is easy, you only have to measure with an ohmmeter. Of the other two to be located, it is a matter of connecting them to and see if it works, in case of not working you only have to exchange the connections. In the case of an incorrect grid and plate connection, it will happen that the intensity of the lamp will be maximum when there is no moderating element that controls the flow of electrons emitted by the cathode, so it should not be left connected for a long time. If you want to do it in a more technical way, you just have to control the current with a millimeter perimeter by subjecting the leg that we do not connect to the positive (plate). by varying that voltage from zero to, for example, less one will have to reduce the intensity between cathode and plate. If that does not happen is that the grid and cathode are inverted.