Hi, please look at the manual.
Anyway, I will give you the code here:
Code:

---

bmap arrow="arrow.tga"; // Your mouse pointer bitmap
// ...
function main()
{
mouse_map=arrow;
mouse_mode=1; // Activate the mouse
// ...
while(1)
{
mouse_pos.x=pointer.x;
mouse_pos.y=pointer.y; // Move the pointer
wait(1);
}
}

---

Regards
TSGames