Teaching Japanese. Any ideas?

Hello, I am a Japanese student who is about to teach my friends Japanese language.

They told me that they are willing to learn grammar, writing and vocabulary in order to sit an exam.

They are complete beginners that do not even know single hiragana, katakana or kanji.(They are from Europe)

I would like to ask foreigners here how you started to learn Japanese; the very first thing you learned.
I am thinking if I should teach how to write Hiragana first which can be quite boring or other vocabulary like greeting or basic things like えんぴつ　りんご　つくえetc with Alphabets.

I am waiting for your opinions or advice!

Thank you.

I learnt hiragana and katakana before taking any classes, but that's where my teacher started (which was good because I found out I'd been writing some kana with incorrect stroke orders). As we learnt the kana we also learnt some basic vocabulary like greetings, colours, numbers, how to say your name, and so on. Then we moved on to daily life/touristic situations such as asking the price of a particular item, how to get to X place, does bus A stop at B, how to order food and drinks, shop opening and closing times, the time, days of the week and of the month...

I think it was only after some 50 hours of classes that we started learning kanji. Based on my experience, and since your friend wants to sit an exam (which, presumably, will be mostly written), it might be best to teach him/her hiragana and katakana with romanisation charts so they associate each kana with a syllable, and also some simple vocabulary.

Espero ter ajudado!

Japanese for Busy People was the text I used.