Where to paste my Facebook pixel event code in my webpage????

Hello,

I have added Facebook pixel base code successfully in my webpage. I have some doubts while installing pixel event code. I copied below pixel code for "Addtobasket".

<script>
fbq('track', 'AddToCart', {
value: 3.50,
currency: 'USD'
});
</script>

I want to know where to add this script and want to know purpose of having this condition (value: 3.50, currency: USD)

I'm running a Indian shopping portal it's currency is INR. Can I remove the condition and simply add like below???

<script>
fbq('track', 'AddToCart');
</script>

If i use code like this whether it is possible to track how many peoples made "add to cart" in my page.

And tell me on which page I have to add this script??? either in home page or each and every webpage???

Thank You