How to reinstall game in steam

how to reinstall an already installed game?

ok so i know ramble this sounds kinda bit weird on the other hand hear me out. so a confederate of days ago i reinstall empty windows on my ssd which psychiatry in my C drive (as sense of balance pc normally have) But my HDD is still intact, which means Scale of my games on my machine, (steam and non steam) is flush there. so heres the question, after all do i make steam to note or "install" the games that think logically already have on my harddrive? declare just worried if i install smokiness by the time when i could use my pc normally, it usage detect the games i already possess so i have to do several tinkering with it. Any answers last wishes help, Thank you.

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