The sentence you provided is a bit unclear. I provided a few translations that may help.
I am not that good at Japanese, so you may want someone to review the following, but I believe them to be correct.
If I were introducing myself to someone I had never met, this is how I would write it.
Konnichiwa Davido-san. (Hello, David)
Watashi wa Belgium ni ikimasu. (I will go to Belgium).
Watashi wa Belgium ni modorimashita. (I returned to Belgium).
watashi wa, Belgium ni kara kaette kimashita. (I came back from Belgium).
*Please let me know if you have any trouble with this answer.
Also I might mention, the word "watashi" is written in Hiragana in the first sentance and Kanji in the remaining two. I hope this didn't confuse you.