I am currently studying the sonnet "Go From Me" written by Browning, but there are a few things I do not understand. Here is the poem : "Go...

Browning here is speaking of transcending the physical distance between her and her lover. He may be taken from her physically, but she nonetheless experiences his presence as real and comforting.

The specific lines you ask about put this sentiment in sensual terms, contrasting the apparent separation and potential for loneliness with the emotional reality of being in communion with one's lover.

For the details, I will translate her poetry into explicit and mundane prose....

Browning here is speaking of transcending the physical distance between her and her lover. He may be taken from her physically, but she nonetheless experiences his presence as real and comforting.

The specific lines you ask about put this sentiment in sensual terms, contrasting the apparent separation and potential for loneliness with the emotional reality of being in communion with one's lover.

For the details, I will translate her poetry into explicit and mundane prose. The original is indented and in quotations. I reset the lines so you can better see the poet's complete thought. My translations follow each quote.

"Nevermore alone upon the threshold of my door of individual life,"

Nevermore when I make my way alone in the world…

" I shall command the uses of my soul, nor lift my hand serenely in the sunshine as before, without the sense of that which I forbore-- Thy touch upon the palm."

…shall I commit acts either of elevated, spiritual meaning ("command the uses of my soul") or simple sensual enjoyment ("lift my hand serenely in the sunshine") without remembering and feeling your physical and emotional presence ("Thy touch upon the palm [of my hand]").

The last part of the excerpt you ask about ("The widest..") needs to be understood in the context of the words that immediately follow.

"The widest land Doom takes to part us, leaves thy heart in mine with pulses beat double."

Here she is saying that even though "Doom" is trying to separate the lovers by putting a great gulf between them, she has, in her mind, his heart as well as hers. They aren't truly cut off by physical distance, because she feels his presence and love in her heart.