‘We’ complete the plural:

Now (with 4a) we fill in the gap for verb endings, with –ο-μεν = we.

Thus for φέρω, ‘carry’, we learned

This works for all the consonant-stem verbs: ἄγω, βαίνω, βαδίζω, ἐλαύνω, καθίζω, κτλ.

But for vowel-stem verbs, like καλ-έ-ω, οἰκ-έ-ω, πον-έ-ω, we have to contract: ε + ο à ου

And don’t forget the irregular ‘be’= εἰμί, εἶ, ἐστί, with plurals ἐσμέν,  ἐστέ, εἰσί.