How to talk to people?

Genuinely need some advice on how to talk to people or something. Idk eveytime I hangout with my best friend or her and her friends I feel so lame, I just sit in the corner on my phone not knowing what to say. Its even worse when im with my best friend and her school friends like my mind goes blank and I just wnana be on my phone. Literally nothing pops into my head about what to talk about, ive never been the type to be talkative but I really want to, I want to be able to talk in groups, I want to be able to make friends. Im an observer so I always see people able to make friends so easily I just want to be able to talk to people you know.

I mostly know what to talk about when stuff has happened you know, like something in my life or whatever. But thats only mostly with my best friend idk what to talk about with new people. And my life hasn't been very eventful lately, so im stumped.

Id really appreciate anything I know some people are able to just talk to pepple like its no problem so id just like to know how, like if theres anything I can do, any advice or whatever. Thank you:]