How to recite the word "تَأۡمَ۬نَّا" in Surah Yusuf Verse 11 (12:11)?

I have heard that there are two Tareeqs in Hafs 'an Aasim to pronouncing this word. What are those Tareeqs, and how exactly to pronounce it? Also, what is Ishmam, should it be done at the beginning, middle, or end of the noon in تَأۡمَ۬نَّا, and how long should it be done in the letter (i.e. briefly or throughout the letter)? Also, is it incorrect to recite the word plainly تَأۡمَنَّا with no special pronounciation? I couldn't find much clear English information on this online, so I am asking it here in hopes it can be clarified and there is a reference for people.