Questions on the activation of aspects in someone's chart

[Mo Tian]

I have another question, I learned that an aspect in someone chart can be activated by a transit or through progression.

For example someone possesses a specific aspect in his chart, let's say the aspect is Saturn/Mars and your Mars has reached a point where it is making an aspect by progression to the Saturn of the person who has the Saturn/Mars aspect.

Now my questions
How do I calculate this progression?
Is it possible to pinpoint a specific moment in time where the conditions are favourable for what is supposed to occur?
How can I take advantage of such arrangements of the stars to make sure that the consequences happen and that they happen between these two people?

Also are there any specific characteristics the person whose planet is progressing to meet the other who has the aspect must have in other to be "acknowledged" by the stars?

And if it's not possible, could you explain the logic behind the activation of aspects that trigger events in one's life?

Let me add that Saturn/Mars is just an example to talk about events that may occur when a planet in someone's chart is making an aspect with another's.

The way I see it specific things whether good or bad happens when the stars are right (I can't believe I'm writing this).
Someone has an appointment with fate in his chart, but the person who is supposed to be the representative of fate on that day is still unknown so maybe it's possible to meddle a bit.

I hope a senior here will be willing to give a junior some pointers in his endeavour.