Hi icetea,
MosFets are controlled by voltage, requiring very little current (somewhere in the µA or nA range)
MosFets do not amplify. They just switch.
You can connect the motor between drain and +VS using an N-channel MosFet. Connect the source directly to ground or via a shunt resistor if you want to measure motor current to use the voltage drop across the shunt to calculate for current.
The gate voltage must be depicted of the data sheet.
A BUZ11 switches OK at a gate voltage of 3 to 5V (better go for 5V, 3V is the lower limit)
Boncuk