For participating in a survey and filling out the questionnaire, your don't have to create an account in Upsteem.com - you can just start answering through a link in email (see "How to start answering the questionnaire").
When you have filled out the questionnaire and confirmed it, you will be provided a possibility to register as a user (set your password). This is not mandatory, but we encourage you to do so - then you can later access the information in which surveys / evaluations you have participated.
If you didn't create an account initially, but later wish to do so, then you need to reset your password. You can do it HERE - just enter your email (that was used when you participated in a survey / evaluation) and you will get the instructions. If you can't remember the email anymore, please contact Upsteem.com support.