Al- (ال) means "the". It joins the start of the word.
Before some letters, called sun letters, the l is not pronounced and the next letter is doubled instead: ash-shams, not al-shams.
l-raḥmānithe Most Graciousl-raḥīmithe Most Mercifulal-ḥamduAll praises and thanksl-ʿālamīnaof the universel-dīni(of the) Judgmentl-ṣirāṭa(to) the path