How do I connect a Samsung sound bar with my tv and apple tv

Apple TV →[HDMI]→ TV →[HDMI ARC/eARC]→ soundbar [1]

or

Apple TV →[HDMI]→ soundbar →[HDMI ARC/eARC]→ TV [2]

[1] Needs eARC on TV for high bandwidth audio passthrough, like Dolby MAT. [2] Needs HDMI-in and HDMI-out on the soundbar for video passthrough.

probably depend on the model

my sonnos soundbar support eARC so it's connected to the eARC enabled hdmi port on my lg tv

and the appletv is connected to one of the other hdmi ports

Use HDMI ARC or eARC with your Apple TV 4K (2nd generation) - Apple Support