Above the windows to the head jamb.

Tension rods if opening/closing (suggest lighter fabric).

Velcro, if stationary

Thank you for the comment.. so essentially like this? (just some old pull shades for example in my photo)

@GN Builders

Go to a pro window-and-blind company and ask. I like the tension rod and softer fabric idea myself, but you sound like you want more privacy.

Is it something you have to close a lot? I think you could do the curtains outside of the window?

Or maybe take down the curvy trim and replace with flat trim so you can mount something onto it?