Turn other's youtube video into my blog post

Hey guys. I'm new in this space. Can I turn someone else youtube video into my blog post? I don't mean word to word but same concept. For example: if there is a video like "5 ways to gain muscle fast" and I turn this video into my blog post am I gonna have problem with google/SEO?

Yes you can do this. Many people are already doing this. Just try to mix it up a bit, use a content/article spinner to help your journey. The articles will probably be low quality, and some of them will be seen as duplicate content if you don't spin them enough, but they are good for inspiration anyways.

You can use voice to speech software to get free content for you blog. First download youtube as mp3 then convert it to text

You can do this. But you should check the plagiarism before posting the content. If someone thinks like you, you can see some duplicate content detection, LOL.