I am new to italki Ryoko and am amazed at how helpful people are and what a wonderful resource this is. If I can help you with your English, please let me know.

I'm glad that you've understood. My English isn't very good yet but I know that each language has its own grammar, ways to say, etc. please enjoy learning and every question is welcome. Best.

Oh yes, I understood that I needed to use すんでいました　perfectly well - and I just realised I made a mistake in my typing and left out the ん　originally. No when I said I didn't realise about the verb tense I meant using the plain present form before 前に。And needing to use the past tense after あとeven when talking about the future - that's what I hadn't realised. Thank you for pointing it out.

Didn't you understand about the form change of すむ to すんで? You have to remember the conjugations like we did in English, like "think --> thought, have --> had". (They aren't "thinked/haved").