How long
Selama covers a stretch of time.
Saya tinggal di sini selama tiga tahun. ‘I lived here for three years.’
Selama liburan. ‘During the holidays.’
Note that selama and selamat are unrelated despite looking alike. Selama is from lama ‘long time’; selamat is ‘safe’.
Since
Sejak Maret. ‘Since March.’
Sejak kecil. ‘Since I was small.’
Dari dulu. ‘For ages, since way back.’
Dari ‘from’, which you know as a place word, also works for time.
Until
Sampai Jumat. ‘Until Friday.’
Dari jam sembilan sampai jam lima. ‘From nine to five.’
Sampai also means to arrive, which is why sampai jumpa ‘see you’ is literally ‘until we meet’.
How long has it been
Sudah berapa lama? ‘How long has it been?’
Sudah tiga bulan. ‘Three months now.’
The sudah carries the “so far” that English puts in the perfect tense. Answering without sudah turns it into a plain duration in the past.
Still to come
lagi placed after a duration means “more”.
Dua hari lagi. ‘Two more days.’
Sebentar lagi. ‘In a moment.’
Sebentar lagi is one of the most-used phrases in the language and its precision is famously loose.
Sebentar and lama
sebentar ‘a short while’
lama ‘a long while’
Tunggu sebentar. ‘Wait a moment.’
Kok lama? ‘What’s taking so long?’
Lama also means old, for things rather than people: rumah lama is an old house, orang tua is an old person.
What you’ll actually hear
What the book says: Saya telah tinggal di Indonesia selama tiga tahun.
What you’ll hear: Udah tiga tahun di sini.