When you slide the top of Pole A into the net sleeve, it should fit comfortably inside. However, if it’s difficult to insert the pole (it seems too wide), loosen the nut on the eye-bolt, screw the eye-bolt further into pole A, and then tighten the nut. This effectively reduces the width of the pole so it can fit inside.
The bottom of Pole A connects with the top of Pole B using a push-pin. If you connect the poles after inserting pole A into the net sleeve, just slide up the sleeve to access the bottom of pole A, make the connection with the top of pole B, and slide the sleeve back into position.
You may choose to keep pole A inside the net sleeve when you dismantle the game. With pole A inside the net sleeve, the net is placed on the white mat, rolled-up and stored in the normal way. Then when it comes time to play, you unroll the net and pole A (left and right) are already in position.