first you have to create a password for the user account.

On your phone, open the terminal and do:
$devel-su
then enter the root password, default is 'rootme' without quotes.
Then you should get # prompt, here do:
#passwd
to change the root password and
#passwd user
to change the user password

after that is done enter these things in winscp
hostname: ip address of phone
username: user
password: newly created password

to get ip address of phone you can do
$hostname -I
in the terminal of the phone.
Your pc and phone must be on the same network.