Name the following compound.

I do not understand how the answer is 3,5-dimethylheptane, because I see only 6 carbon strands with the exception of the ethyl strand and the methyl strand, so it should be hexane, but the answer is heptane somehow. im also confused to how they get dimethyl from the structure because I see a ethyl structure at the 5th carbon strand and a methyl strand at 3, im not sure if my teacher forgot to teach us or something but I have no idea how 3,5-dimethylheptane is the answer, please tell me what I did wrong and show the steps, or let me know if the answer is incorrect, thank you