'-도' has meaning of 'and', 'again' "as well" like that.
"오늘도 내 기억을 따라헤매다" should be "Today, i wander in my memory AGAIN."
Or before the sentence, there should be a sentence like " I wanderED in my mermory yersterday (in the past)."
A : I like you. 나는 널 좋아해
B: I like you, too 나도 널 좋아해.
He bought a camera. And few days later, my brother bought the same.
나는 카메라를 샀다. 며칠 뒤 동생도 같은 걸 샀다.
샀어 is spoken Korean. 샀다 is written Korean.
걸(spoken Kor) is short for '것을'
것 = thing (in the sentence), 같은 것 = the same thing