Request for Noob guide fpr TWRP recovery

This is a friendly request to all the dev$ …..
Guys I tried to install cosmic rom by using twrp recovery but every time my device stucks in boot loop…although by flash firmware I make it to work…
I think I am commiting some mistakes in installing COSMIC ROM via TWRP recovery…..
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I request u guys to plz provide us the best step by step noob guide for using TWRP recovery and installation of ROM via Twrp….
Its a humble request guys