andresilva:
1 - The Uno that I use to program can be used to see the serial output or should I connect the attiny to another Uno that excuta a code just to get data that it receives via serial and prints to the monitor?
You have two options:
You can use the Uno as a dumb USB-TTL serial adapter by connecting the TX pin on your ATtiny85 to the pin marked TX on the Uno. You will need to make sure there is no sketch running on the Uno that will interfere with serial communication between the ATtiny85 and your computer.
You can run a sketch on the Uno that echos communication between a software serial port and Serial. For this you would need to connect the ATtiny85 to whatever software serial pin(s) you have defined in your sketch for the Uno. You can use File > Examples > 04.Communication > SerialPassthrough as an start for your sketch on the Uno but you need to modify it to use SoftwareSerial instead of hardware serial port Serial1 since Uno does not have Serial1.
I would actually prefer to just buy a dedicated USB-TTL serial adapter board rather than trying to use the Uno for this purpose. You can get them very cheap and they're a really useful tool.
andresilva:
2 - I was to make the attiny TX connection on PB0 and "const int tx = 2;" change to 0 instead of 2 and continue connecting the RX-0 port on Uno?
Just make sure that the Arduino pin you defined for SoftwareSerial matches the physical pin you have the wire connected to.