Al-Qantarah is a small bridge after the Siraat that the believers will have to cross before entering Jannah. Allah (سبحانه وتعالى) will ask the believers to settle their issues here.

What is the arch before Jannah?

As-Sirāt (Arabic: الصراط‎ aṣ-ṣirāṭ) is, according to Islam, the bridge which every human must pass on the Yawm al-Qiyamah ("Day of Resurrection") to enter Paradise.

What Jannah means?

In Islam, Jannah (Arabic: جنّة‎ Jannah; plural: Jannat, Turkish: Cennet), lit. "paradise, garden", is the final abode of the righteous and the Islamic believers, The Garden of Eden, where Adam and Hawa dwelt is also called Jannah. ... However, "Firdaus" also designates the highest level of heaven.