https://www.nctionline.com/Registration/register.aspx?form=IQ
This will get you into the registration site, the courses are some what pricey, but you can test out for $75 for each topic without taking the courses. You get two chances to test and if you don't pass then you have to take the course. The HSD is difficult because from an installation perspective we don't really have to deal with provisioning and there are a good amount questions on that. The QSI and VOIP are not nearly as difficult and better relate to day to day installation practices. Hope this helps.