Connect ESP-01 to USB Uart for programming my ESP-01 chip I bought an "USB Uart", but it looks different to all the ones in all tutorials. I don't know how to connect the uart to the esp.
The uart i bought has following pins: 3V3, DTR, RXI, TX0, GND, +5V. The ESP01 has the known layout (http://www.esp8266.com/wiki/doku.php?id=esp8266-module-family#esp-01). 

Once connected: Do I need an external power source, or do i just connect the usb uart to my computer?

Many thanks
Just to give an anwser for users struggling with the same problem I will sum up what helped me.

To connect the UART to the ESP the Beginner's Guide to the ESP8266 from @tttapa was very helpful. Another helpful link was this one:
https://www.allaboutcircuits.com/projects/flashing-the-ESP-01-firmware-to-SDK-v2.0.0-is-easier-now/

So in my case I just needed the GND, 3V3, RXI and TX0 pins from my UART.

I needed no external powersupply for the flashing process and some simple examples.