As a learning resource the Survey (portfolio) can be created in the authoring section and after that be added to a portfolio template.
Add a title and save the survey. As soon as the survey is created open the editor under Tools with "Edit content". The editor for the creation of the survey opens.
Some edit options are the same as for the assignment in the portfolio. So you can add for example a title and a heading, write a text, add separators or upload a file. Further information you can find here.
In addition to the mentioned elements you can add rubrics and text input fields. Available rubrics types are:
Discrete with Radio
Discrete with Slider
Adding a text input you only have to specify the number of rows. This defines the shown size of the text field, but does not limit the number of rows. Thus a user can insert more text then the given rows.
Then the Survey (Portfolio) is saved in the authoring and can be added to the portfolio assignment.