I`ll try my best with explanation, but as I am having a mayor headache and insomnia, then I hope someone will correct the mistakes that I might make.
was/were- past simple, right? I was- ma olin
you were- sa olid
he/she was- ta oli
we were- me olime
you were- te olite
they were- nad olid
(It seems more simple in English)
has/have been-present perfect, eh? I have been- ma olen olnud
you have been- sa oled olnud
he/she have been- ta on olnud
we have been- me oleme olnud
you have been- te olete olnud
they have been- nad on olnud
(the first part is like "to be" in present and you just add "olnud")
had been- past perfect..probably..
You take past simple of "To be" (olema) and add "olnud". I start to see some kind of pattern here... I had been- ma olin olnud
you had been- sa olid olnud
he/she had been- ta oli olnud
we had been- me olime olnud
you had been- te olite olnud
they had been- nad olid olnud
I hope that too...
And by the way... Suslik, did we reply almost at the same time to this topic..as i got a notification that you had replied to this topic, but here isn`t your reply anywhere... Now I am confused...