What does allowing emotions and still keeping your "S" together look like in the beginning?

I’m in a spot where I know I need to allow my emotions… I’m already overthinking this. Wondering what does this look like? What does it feel like to not resist? How do I handle that? How do I ALLOW an emotion (especially one that I’ve been really resisting) and at the same time keep my shit together? If I allow anger or sadness and I’m hanging out with my kids at the park or something… I’m just trying to figure out what that looks like so that I can allow and no longer resist… Thanks!