PR with points: Japanese National Qualifications

Hello

I am planning on applying for PR via the point system January of next year.

I am a bit worried about the points gained from having a Japanese National Qualification. I have one of the IT qualifications. My previous job (within this year) was in the IT field, but I switched to telecommunicating. Would this be a problem since the description says it has to be related to the work you do?

One more thing, I am planning to do the application by myself. From what I understand, I just need to prepare the documents as defined in the below link and go to the nearest immigrantion office, right?
https://www.moj.go.jp/isa/applications/status/designatedactivities02_00004.html

Thanks so much!