The steps to log in for the first time B2B or recover your user password would be: 

1) Log in B2B

2)  In I am already a customer section click on "Don't have a password yet"?

      or " I forgot my password"  - in case you have already set up a password but you do not rememeber. 

3) Introduce you company tax number.

4) Click on "Send email" to via emil receive the pasword to get acces to B2B.