you first need to decide which variables are dependent, and which ones are independent...

What are your research questions?

If you have 2 independent / 1 dependent variable, then do multiple regression.

If you have 1 independent / 2 dependent variables, then:

- do multivariate regression if it makes sense to combine the 2 dependent variables

- do separate simple regressions if it does not make sense to combine the 2 dependent variables