Hi,
With the very basics I mean knowing how to read Hangul, how to form sentences, and simple tenses and particles. 1-1 covers grammar points like 입니다/입니까, 은/는, 이/가, 을.를, 에(서), 이/그/저, 에, 하고, 과/와, ~세요, (으)로, 부터~까지, 아/어요, 안, 았/었, 도.

I´d advise you to take a look at the table of contents of all Ewha books to check out the grammar points they´re teaching in each book. You can find screenshots of the table of contents and sometimes dialogues on the website of Twochois (works better on my laptop than mobile). A TTMIK level doesn’t cover the same points as one Ewha book, but I’d say you can probably start with 2-1 (see screenshots) or 2-2 (see screenshots).

By the way, the 이야기 series of TTMIK is 100% in Korean. So when you reach upper beginner or intermediate level, you might find it interesting again.

Kind regards,
Kim