This schematic was made by using the Fritzing Software">
The Si5351A is connected to D2 (SDA) and D3 (SCL).
The OLED is connected to D2 (SDA) and D3 (SCL). Yes, the same Si5351A connections.
Connect Arduino D8 and D9 pins to the Encoder pin A and pin B respectively.
Connect Arduino D1/Tx pin to the Step push button (S1).
Connect Arduino D0 pin to the Reset BFO push button (S2).
Connect the Arduino pin D7 to the BFO On/Off push button (S3).