The origin of Replication is recognized by DNA A protein complex
then Helicase starts to separate the Double strands into single strands
Single stranded binding protein binds each strand preventing Reannealing
DNA polymerase enzyme moves along the single strand copying a complementary strand (actually it adds nucleotides to a primer made by enzyme called primase) on the leading strand which the enzyme moves from 5 to 3 prime continuously uninterrupted but on the other strand (lagging) the enzyme moves in the same direction 5 to 3 prime but not continuously making small fragments called okazaki fragments then they are joined by ligase forming a complete strand .
the process ends with 2 new double strands each of them contains single strand from the parent strand and the other is new strand this is why it is called semi-conservative replication