I think it would be difficult to piece together what each person has recorded.
Putting together what each person has recorded could be difficult.
ご質問ありがとうございます。
① "I think it would be difficult"＝「それは難しいと私は思う」
"to piece together what each person has recorded."＝「一人一人が録画したものをつなぎあわせることは。」
② "Putting together what each person has recorded"＝「各人が録画したものを一緒にすることは」
"could be difficult."＝「難しいかもしれない。」
ご参考に。
アメリカ合衆国 
