Please read these documents sequentially, one by one.

sequentially 是形容词 sequential 的副词形式，由词根 sequ-（表示"跟随、顺序"）和后缀 -ent（形容词后缀）加上 -ial（形容词后缀）构成，最后加上 -ly 变成副词。意思是"按顺序地、连续地"。