You description doesn't match the drawing.
You show the soundbar as having two HDMI inputs plus one HDMI output. You say it has 1 HDMI input and 1 output (which is more likely).
Does your TV have 2 or 3 HDMI inputs (one marked HDMI-ARC)?
If it has 3 then you can connect the soundbar to one marked HDMI-ARC and connect one of the sources to its' HDMI input. The other two connect directly to the TV.
An alternative would be to connect all your sources directly to the TV with HDMI and use the TV audio output to connect the soundbar. That's the way I would do it. No advantage to using ARC.
If it has 2 HDMI inputs then you will need an HDMI input selector to expand the number of inputs.