land a glove on sb, & deliver the knock-out punch, etc,
Jeffrey Archer's "False Impression":
(Macy and Jack are FBI agents),
Macy had also made it clear that he hoped Jack would take over from him once he was transferred back to Washington DC. But before that could happen, Jack still had to put in jail a man who was turning any such thoughts of promotion into fantasies. And so far, Jack had to admit, he hadn't so much as landed a glove on Bryce Fenston, and was now having to rely on an amateur to deliver the knock-out punch.
question:
1. take over from
2. turning any shuch thoughts of promotion into fantasies.
3. land a glove on Bryce Fenston
4. deliver the knock-out punch
On the whole , I completely don't quite understand this sentence , \
please help me and thank you so much,

Question

land a glove on sb,  & deliver the knock-out punch, etc, 
Jeffrey Archer's "False Impression":
(Macy and Jack are FBI agents),
Macy had also made it clear that he hoped Jack would take over from him once he was transferred back to Washington DC. But before that could happen, Jack still had to put in jail a man who was turning any  such thoughts of promotion into fantasies. And so far, Jack had to admit, he hadn't so much as landed a glove on Bryce Fenston, and was now having to rely on an amateur to deliver the knock-out punch.
question:
1. take over from
2. turning any shuch thoughts of promotion into fantasies.
3. land a glove on Bryce Fenston
4. deliver the knock-out punch
On the whole , I completely don't quite understand this sentence , \
please help me and thank you so much,

Answer

1. take over from - Jack would replace Macy in his role.

2. turning any such thoughts of promotion into fantasies. - It means that the man who Jack had to put in prison (jail) was creating the impression that Jack was incompetent. So Jack who was dreaming of replacing Macy thought that he would not get to replace Macy. So the dream would become a fantasy.

3. land a glove on Bryce Fenston - this is a boxing term. It means to hit someone or to connect a punch with a gloved hand. So Jack had not yet been able to prove anything about Bryce - "he had not landed a metaphorical punch"

4. deliver the knock-out punch - another boxing term. Knock-out punches end fights.

So Jack is saying that someone else (an amateur) is going to end Bryce's career.
 Looking at this in a wider sense, Jack is saying that he is a professional and cannot prove Bryce is guilty, but an amateur is proving Bryce guilty.

It is an  allusion  to the commonly encountered terms "professional boxer" and "amateur boxer"