Normally, if you switch on transmitter, the signal will be connected automatically. Try if it is connected, by opening Radio tap, move left right joysticks or Handle VrA VrB. You should see the slider responding.
Be aware that, the transmitter does not neccessarily show RX battery IntV1 and Err1. It depends on the version of drone and receiver you are using.
Start your radio calibration following the instruction COEX RC setup.