I am new to l298n h bridge motor driver and i do not know how to connect motors to it
please help
and also
ow do we know the positive and negative side of arduino
Your question seems to have no relation to the Title of your Thread. A better Title would seem to be "How to use an L298n with an Arduino". If you edit your Original Post you can change the Title.
It will also help if you tell us what Arduino board you are using.
I don't know what you had in mind when you wrote "ow do we know the positive and negative side of arduino"
An Arduino is not a power supply like a battery. The Arduino I/O pins are used to send control signals to the L298 and the Arduino GND also needs to be connected to the L298.
Separately you need to connect the motor power supply to the L298.
I suspect that Google will be able to find you dozens of connection diagrams
...R
Your question suggests your Arduino is in an imminent threat of being destroyed. Do more simple projects, learn how motors and control circuits work. Learn why and how an h bridge works. Start from the blink sketch in Arduino examples. Hand gesture controlled robot is nowhere near a beginner-friendly project for getting into electronics. Google, google and google again.