What do you understand by the phrase, “When I wasn’t in the crow’s nest?

On a ship, the crow's nest is a small platform high up on the mast, where a person can go to look in all directions.

So the phrase, " When I wasn't in the crow's nest could have many different interpretation, depending on the way you look at it. My interpretation of the phrase is that you can see all directions in the crows nest of a ship. When you aren't in the crows nest you can't see all directions. So the crow's nest could symbolise you didn't know where you were going or what you were doing something in life for. In addition, it could syblolise you were blind to your surroundings or you had no purpose in life. These are jyst a few interpretations I have of the phrase but obviously, everybody's interpretations are different.

you need to explain that more, your grammer just needs to be close to perfect.

edwards uses the phrase "o who can express what the state of a soul in such circumstances is! " in order to illustrate that this type of suffering is unimaginable. the word "express" denoted that the state of a suffering soul is required to be described by any person, but it would not happen because no one can imagine how this suffering is felt.  

-show what might happen if the reader disobeys edwards is not correct because this is described trhough the text, not by the phrase used.

-describe what endless suffering looks and feels like is not correct because this description might be the porpuse of the excerpt provided, not the porpuse of using the phrase during the writting.

-prove that few people have survived limitless suffering is not correct because it is implied that the soul of a person is already suffering and doesn't have any way to escape.