In english, the 'been' is a way of signaling that you're talking about the past, about something that is ongoing. 

If you say for example. 'Eu trabalhei' it means that you worked and that it's done. To talk about some action that is ongoing you combine the verb TER + verb (past participle). So to say 'I've been working' it's eu TENHO trabalhADO.

And to ask, 'What have you thinking' it's o que você TEM pensADparticiplO?

Simple!

In the Portuguese present perfect you can express this type of 'have been' by combining TER with any verb in it's past participle form!

Let's do an ER verb:

'Iv'e been eating a lot' >> eu TENHO comIDO muito'

How about an irregular verb like, FAZER?

'What have you been doing?' >> o que você TEM feito?

You need to know the past participles of verbs! This conjugation is called the Present Perfect Indicative and it's really, really useful so: learn it now!

More examples:

'What have you been thinking?' >> O que você tem pensado?'

'We've been watching a lot of movies.' >> Nós temos assistido muitos filmes.

'They've been going out every day!' >> Eles têm saido todos os dias!