After specifying your desired contact, you can send a connection request via one of two ways.
The first way
Click Connect to send your connection request.
The second way
Access the profile page of the contact to whom you want to send a connection request, then click Invite to connect at the right corner of the profile page.
Note
If you follow the first way, the Connect text will become Cancel Request. Meanwhile, if you follow the second way, the Invite to connect text will be turned into Revoke.