newbe question on view for a 1:n model

I want do build a view for a 1:n model for funtion new.

Rendering the form for the attributes of the independent (1) record is
done automatically.

But how to create the variable number of inputs for the dependent (n)

Look for the railscast series on complex forms (# 73-75).

In a nutshell you'll need to use Ajax to dynamically add input
elements and pass all the values of those elements to the controller
in an array.