Variable size arrays

Hi all, I'm having trouble with arrays ( Yes I'm new to C )

Here is what I want to do in a nutshell:

#include <stdio.h>

main ()
{
printf("Please input the size of the array you want");
int arrsize;
scanf("%d",&arrsize);
int myarray [arrsize];
}

I can't do that so I've been experimenting with malloc and have come up with this:

int arrsize;
scanf("%d",&arrsize);
int *numptr;
numptr = (int *) malloc (arrsize);

This is where I'm stuck, now I've got this chunk of memory ( is it the right size? ) how can I make it so it acts as an array.
IE

myarray [0]
myarray [1]
...
myarray [arrsize]

Thanks in advance for any help.

numptr = (int *) malloc (sizeof (int) * arrsize);

thanks, will I then be able to use that memory space as an array. If so how do I access it?

I want to add numbers to each each member of the array like this ideally:

int i;
for (i=0;i<=arrsize;i++) {
myarray[i] = i;
}

Any ideas

Pointers and dynamic allocation etc

That's the full details anyways, but there are also plenty of examples on here if you look for them.

Good link thanks, I've sorted my problem now.