[Help: English Gurus] Starting an English Curriculum

A friend of mine plans to start a small English school for underprivileged kids here in SE Asia. Well it's actually her and a few friends (I think). They speak decent English for someone who grew up in a non-English environment. If you put it in ESL terms, they're probably in the advance level.

Recently my friend asked me if I could help out with starting a curriculum since I'm the only person she knows who speaks English fluently. I know she and her friends are good people so I told them I'll see what I can do. Then I realized, I have absolutely no idea what the hell I'm doing.

So basically I'm starting this from scratch, meaning I have to create some kind of a placement test to measure the kids' abilities. Then from there we'll have to create lessons for each level. I'm thinking maybe like a Beginner, Intermediate, Advance level would be a good start?

The kids are going to be aged from elementary to high school, so I assume they'll have varying degrees of English abilities, although probably not much higher than ESL intermediate level.

I know there are some teachers here, so anyone have any ideas where I can look for some good placement tests? Or how to create one? Any websites that you know can help me create a good English curriculum and lessons? TBH I'm not too familiar with the details of the grammar rules and names. So maybe this is a good opportunity for me to learn as well.

Also I'm sure there are more than just creating a placement test and lesson plans, so any other input would be greatly appreciated. :grin: