This is more than likely in relation to the form type attached to the step. For example, if you are trying to add a ‘Questionnaire’ to your Personal Information Step (Step 1), this step only allows you to add a ‘Candidate PIF’, hence why you wouldn’t be able to find the form.

Against each step, you will see the form type which will help you;

It may be helpful to take a look under ‘Forms/Questionnaires’ within your environment to ensure the form you are trying to find hasn’t been archived;