וְאֵ֗לֶּה שְׁמוֹת֙ בְּנֵ֣י יִשְׁמָעֵ֔אל בִּשְׁמֹתָ֖ם לְתוֹלְדֹתָ֑ם בְּכֹ֤ר יִשְׁמָעֵאל֙ נְבָיֹ֔ת וְקֵדָ֥ר וְאַדְבְּאֵ֖ל וּמִבְשָֽׂם׃
И это имена сыновей Измаила по именам их по поколениям: первенец Измаил, Небайот; и Кедар, и Адбиил, и Мибсам,
Rashi on Genesis
בשמתם לתולדתם BY THEIR NAMES ACCORDING TO THEIR PROGENY — by the order in which they were born one after the other.
Radak on Genesis
ואלה...לתולדותם, in the chronological order of their birth. The firstborn of them all was Nevayot.
Siftei Chakhamim
In order of their birth, one after another. Rashi is saying that בשמותם לתולדותם means, [“Their names] in the order of their birth.” Otherwise, why is this phrase said? This explains why it says afterwards, “Nevayos was Yishmael’s first born.”