Both sentences 1 and 2 are correct. They both refer to something that will occur in the future. The second sentence is present perfect and refers to the completion of the process of going through the book, and after indicates that we are specifying what happens after the completion. The first sentence refers to the entire process of going through the book: because of the after, we understand that we are still talking about what happens once the entire process is completed.
Sentence 3 is past simple, so it refers to an event in the past. after defines what happened after this event. after she had been signed is past perfect: it would make a grammatically correct sentence, but we generally only use past perfect if we really need to. In this case, simple past is sufficient to convey the correct meaning.
Looking at the following example sentences, a and b are both grammatically correct and mean the same thing. In both sentences, before places the eating before the arrival, so past perfect is not required: sentence a is the best option.
Sentences c and d are both grammatically correct, but have different meanings because when suggests simultaneity rather than sequence. In c, simple past places the eating at the same time as the arrival, but in d, past perfect places the eating before the arrival (or in practice directly afterwards). If the eating did take place before the arrival, the use of past perfect is necessary, so sentence d is the only one that fits what happened.
a) I ate before he arrived
b) I had eaten before he arrived
c) I ate when he arrived
d) I had eaten when he arrived