1. You can leave UTN section, Thats not mandatory.

2. Give total tax deducted . Each row is for one employer.

3. You can fill previous year tax return also.

4. Either you should send the ack form in A4 size envelop or fold in such a way that the bar code at the bottom of the sheet is not folded.

5. the password of your ack form is your pan number in small later followed by DOB in ddmmyyyy formate .

6.* Please read instruction carefully and you will get most of your answers.
And Yes, you can contact call center Aayakar Sampark Kendra (ASK) on phone number 0124-2438000 for assistance.
https://incometaxin diaefiling. gov.in/portal/ faq_process. do