1."particle marking the following noun as a direct object" seems to be what "把" serves as in your sentence .And this is how that particular function of "把" is explained in a Chinese Dictionary:"用在宾语之前,宾语之后跟着及物动词,表示处置,致使或动作行为的结果" example: 请把门关上 . 门:宾语 关上:及物动词 2.yes,"从一开始" means "from the beginning".

“把” is opposit to "被"(passive), so you can think about the "passive voice" in englich, to understand the opposit.