Is it as simple as 2 raka'at x 4 which is a total of 8 raka'at or is it different Also what are the surahs that are recited
Tahajjud (Night prayer)
It is a voluntary prayer and a best way to purify the soul. Tahajjud Prayer does not entail a specific number of rak`ahs that must be performed.
Moreover, performing Tahajjud prayers regularly qualifies one as one of the righteous and helps one earn God's bounty and mercy.
God says :
And from [part of] the night, pray with it as additional [worship] for you; it is expected that your Lord will resurrect you to a praised station.(isra,79)
Number of rakaats and time
I practice tahajjud prayer starting with two rakat followed by two rakat and (so on) and finish with one rakat. I usually recite the surahs, the one i know its translation too (yusuf,isra,yunus..etc). The time i pray usually between (3:30-fajr).