Once you are approved, your SW starts searching for your child.
Mostly, people's SW's bring them profiles to read. If you read the profile and want to go further, you get the childs CPR and read that. That's your 'potential link'. Alternately some parents use the waiting child magazines (BMP and CWW) or go to exchange days and find a child there. If you find a child in this way, you get your SW to request the childs CPR to read.
If you still want to go ahead after that, then it's up to the childs SW to decide whether he/she wants you. You will have a meeting with the childs SW who will then make a decision about whether they also want to progress
If the SW says yes, you're 'linked'
Now you go on to read more about the child, get updated information, maybe a DVD, meet the foster carers, meet medical professionals if necessary, have a life-appreciation day if your agency do them. At this stage it's possible that something could go wrong, you might recieve information that wasn't in the CPR that causes you to realise this isn't the right match etc
Once you've got all the information you need, and you and the SW's are still happy, they will book a matching panel. Panel recieve information on you and the child and then you go to panel, they ask you and your social worker questions, and then they recommend whether you should be matched. The decision maker ratifies it
Once panel say yes, you are "matched". You will recieve a matching certificate, which you need to show your employer to start your adoption leave.
Once you are officially matched you can meet your child, so the final planning for introductions will happen.
You do your introductions. Your child becomes "placed" on the day you take them home ie. they move in with you full time.
Being linked is an unofficial term, but placed and matched are legal terms which have legal ramifications (for instance, once a child is placed with adoptive parents, the BP's cannot ask to have the placement order revoked. They have to wait until the adopters apply for the adoption order, and then try and oppose that)