These Practice pages can be utilized in several ways.

The recommended method is for two partners to be in vocal contact, each looking at the page in a different computer - perhaps one with a laptop. Using this method one partner would start by clicking on NORTH, the other on SOUTH.

Somewhat less satisfactorily, the partners can use a single computer, and alternate looking at the display, again one as NORTH, the other as SOUTH.

As a last resort, one person can click back and forth between screens.

Start by clicking one of the buttons; when the bidding is complete click the BIDDING button to check the "recommended" bidding.
 Your partner, SOUTH, is the Dealer.
 Bid this hand together.
 The opponents do not bid.
 You are the Dealer.
 Bid this hand with your partner.
 The opponents do not bid.
pass7♠all pass

SOUTH opens 2♣ and is pleased when NORTH makes a positive response of 2♠. His first step is to set the trump suit by bidding 3♠. There is NO chance that NORTH will pass.

NORTH now bids 4♣ a Control-showing bid.
SOUTH continues Control-showing with 4.

That's enough for NORTH to hear. She invokes Blackwood and learning they have all the Aces bids 7♠.
♠ A J 9 8 3
K 7 2
♣ A 8 7 4

♠ K Q 10 2
A Q J 10 5
A K 2
♣ K