What are the various types of ink filling of a fountain pen?

Piston filling: Remove the cap. Turn the bottom counterclockwise, but not too much (fig.1). Dip the nib in the ink. Turn the case back clockwise to return it to its initial position (fig.2). If it is the first time that you use this type of fountain pen, leave the nib in the ink and rotate the bottom back again. Remove the pen from the ink, turn the bottom counterclockwise and let 3 drops of ink come out (fig. 3). Position the pen with the nib facing upwards and rotate the case back to the initial position (excess ink will re-enter) (fig. 4). Dry with a soft cloth to absorb the extra ink on the nib or tank.

Cartridge or plunger converter filling: To fill, pull the cap. Unscrew the front of the pen (fig.1). Cartridge: insert an Aurora type K / S cartridge (fig. 2). Screw the tank back on and after a few moments you can start writing. Plunger converter: insert the Aurora plunger converter until it clicks. Turn the plunger anticlockwise (fig.3). Immerse the nib completely in the ink and turn the plunger clockwise (fig. 4). At this point, rotate the plunger anticlockwise again to release a drop of ink. Now dry with a soft cloth that absorbs any excess ink from the nib.