The Suhuf of Ibrahim and Musa

S 53:36-37 Or was not informed of what is in the sheets of Musa / And Ibrahim who completed?

S 87:18-19 This is in the first sheets. / Ibrahim’s and Musa’s sheets.

As 'sheets' translates an Arabic plural (three or more), how many did they both have? What is meant by 'first' sheets? Were they scriptures? They were apparently extant in the author's lifetime; where are they now? Were Ibrahim and Musa contemporaries?

Definitions for sahifah (the singular):

Noun

صَحِيفَة • (ṣaḥīfa) f (plural صُحُف‎ (ṣuḥuf) or صَحَائِف‎ (ṣaḥāʔif))

1. newspaper synonym ▲Synonym: جَرِيدَة‎ (jarīda)

2. journal, ephemeris

3. a loose piece of paper on which has been written, a sheet, letters, paper quotations ▼

4. an amount of paper in a bound work, a page or leaf of a physical book, a sheet such as a كُرَّاسَة‎ (kurrāsa), record

5. surface, exterior, outer skin, epidermis

https://en.m.wiktionary.org/wiki/%D8%B5%D8%AD%D9%8A%D9%81%D8%A9#Arabic