Dual Boot

Im trying to be tech savvy. Got my CCNA but really that’s all the knowledge I have in regards to any kind of technological stuff. Right know im trying to dual boot my lenovo adding Debian 13. Things didn’t go so well, tried to fix it with chat GPT. Got upset and decided to uninstall it on my phone and to never use it again (eventually I will change my mind probably). Now im trying to understand the process and do it by myself. Is there a reasonable well explained resource where I can learn what involves dual booting a machine that isn’t a straightforward YouTube video? Is it recommended to just format my SSD and just start all over again? I installed Debian in a different drive and already backed all my info. Do you have questions that you think I should start asking? Thanks.