RULES question??? Quick Question

[IbrakeFORrivers]

Board:

3 [img]/images/graemlins/heart.gif[/img], 5 [img]/images/graemlins/heart.gif[/img], 2 [img]/images/graemlins/spade.gif[/img], 4 [img]/images/graemlins/club.gif[/img], 5 [img]/images/graemlins/spade.gif[/img]

My hand:

6 [img]/images/graemlins/spade.gif[/img], 10 [img]/images/graemlins/spade.gif[/img], 10 [img]/images/graemlins/diamond.gif[/img], A [img]/images/graemlins/diamond.gif[/img]

Turns out i won the HI and the LO,
Hi with 2-pair, 10s and 5's, and the LO with
A, 2, 3, 4, 6.

Someone explain this. I thought i won with the 2 to 6 straight, and obviously, the hi with the A2345.

I thought you can only use 2 cards?!?!

Now i can use 4, but each one un-repitively?

Someone please explain? thanks. Yes i'm a newb.