According to the application procedure that was written on the manual posted on their webpage...
I checked how to file the application on the manual that was on their webpage.
ご質問ありがとうございます。
① "According to the application procedure"＝「申請の手続きは」
"that was written on the manual posted on their webpage..."＝「彼等のウェブページに掲載されていたマニュアルによると...」
② "I checked how to file the application on the manual that was on their webpage."＝「どのように申請するのか、彼らのウェブページに載っていたマニュアルで確認しました。」
ご参考までに。
アメリカ合衆国 
