To recharge a toy with a minijack cable, simply insert the cable into the appropriate hole that you will find next to the DC symbol.
To preserve the internal motor and allow correct maintenance, the hole is usually covered with a thin layer of silicone: to drill it, press a little with the tip of the cable the first time you recharge the toy. When you disconnect the cable, the silicone will close again and the toy will be protected from possible infiltration of liquids.
To recharge a toy with a magnetic cable, simply place the cable on the magnets so that they remain attached; you can help yourself by leaving the toy charging on a flat surface.
When a toy is charging, the light on the toy will normally begin to flash. When the toy is charged the light will become solid.
Remember that the power supply you use must have the voltage and amperage indicated in the instructions; a more powerful power supply could damage the toy's battery.