The illustrations show the main forty card set of Usk Cards. The remaining 16 cards are in the box. I would suggest using fewer cards, especially at first: maybe 3-4-5-6 each one 'four-ways' (= 16 cards). Split the cards into two equal piles, one for each player (North and South in these pictures.)
We show two coloured 'patches'. Ours are made of artificial felt - but paper would do well. (The felt makes it easier for small fingers to pick-up the cards, or even slide them off the edge.)
The aim is to remove cards from the patches and build your own families of numerically matching cards. Suggested rule: each player only plays from his/her own patch. In theory the patches will be empty by the time the last card is drawn. Winner is: as the umpire decides!
S turns over a card onto her patch
N turns over a card onto his patch
S turns over a second card
N turns over his second card
S now has three cards
N turns over his third card a'6'
S fills the last available space on her patch
The matching pairs are claimed by S as 'hers'
S has another turn: a reward for completing a match
S is clearly on a winning streak: and has another turn. (Maybe the 'extra turn' rules needs modification?)
S
N
S
N