Learn Arabic (Modern Standard): الإجراء الثاني هو أن نتأكد من الهوية قبل أن نقرأ الملف. - The second procedure is that we make sure of the identity before we read the file.

You use قبل (before) when the next word is a noun, like 'before the meeting'. But when 'before' is followed by a new action/verb (like 'before we read'), you must use قبل أن. The أن acts as a bridge connecting the time word to the verb clause.

How does أن affect the verbs نتأكد (we make sure) and نقرأ (we read)?

The particle أن forces the following present tense verb into the subjunctive state. For 'we' verbs like these, it means the final short vowel changes from a standard 'damma' (u-sound) to a 'fatha' (a-sound). If you read with full vowels, they are pronounced nata'akkada and naqra'a.

Why is the word هو (he/it) sitting in the middle of the sentence?

Here, هو acts as a linking word (a copula) meaning 'is'. Because Arabic doesn't have a regular present tense verb for 'to be', هو is often inserted to separate the subject (الإجراء الثاني, the second procedure) from the rest of the sentence, making it crystal clear where the subject ends and the main point begins.

Why do we say نتأكد من (make sure from) instead of translating 'make sure of' directly?

Arabic verbs often pair with specific prepositions that don't match English exactly. The verb تأكد (to make sure / to be certain) always pairs with من (from). You cannot use it without this preposition when mentioning what you are checking.