Can i conect leonardo to uno using serial?

I want to conecting leonardo as an input and uno as an input by using serial ?
Please help me !!!I
I confused about the serial conection because the rx tx port not open properly witout open the serial monitor
how can i fix that?

Leonardo Rx to Uno Tx, Tx to Rx, Gnd to Gnd.
Have not used Leonardo - Serial() is the USB interface, and Serial1 is the UART to outside world?