The three futures
Saya mau pergi. ‘I’m going to go.’ Everyday.
Saya akan pergi. ‘I will go.’ Formal, written.
Saya pergi besok. ‘I’m going tomorrow.’ No marker at all.
The third is the most common. Once a time word is present, nothing else is needed, and Indonesian prefers to say less.
Arranging to meet
Ketemu di mana? ‘Where shall we meet?’
Ketemu jam berapa? ‘What time?’
Besok bisa? ‘Can you do tomorrow?’
Ketemu is the casual form of bertemu, and it is what everyone says.
Rencana
Ada rencana akhir pekan? ‘Any plans this weekend?’
Belum ada rencana. ‘No plans yet.’
Note belum again rather than tidak. Saying tidak ada rencana sounds like you are declaring yourself unavailable.
The vagueness is deliberate
An Indonesian yes to a plan is often soft on purpose, because a firm commitment that later fails costs more face than a vague one.
Nanti saya kabari. ‘I’ll let you know later.’
Kalau sempat. ‘If I get the chance.’
Insya Allah. ‘God willing.’
That last one is used across the country by Muslim speakers, and in practice it ranges from a firm yes to a polite no depending on tone and context.
None of this is evasion. It is a system where plans stay adjustable until they happen, and an English speaker who reads any of these as a confirmed appointment will be disappointed and will misread the situation.
Getting a firm answer
Make it easy to decline, exactly as with refusals in A1.
Kalau nggak bisa, nggak apa-apa. ‘If you can’t, that’s fine.’
Then a yes means yes.
What you’ll actually hear
What the book says: Saya akan menghubungi Anda nanti.
What you’ll hear: Nanti aku kabarin.