How to connect led?

[Krafti]

I just bought stm32 and i cant find any guides how can i enable led. I flashed pin PB7 so that it would output current

[STTwo-32]

Hello @Krafti @and welcome to the ST Community. 
This is not an ST official evaluation board but it is a Board based on an STM32 MCU. So, you should ask the manufacturer of this board about the connections and the board layout. 
‘Best Regards.
STTwo-32

[TDK]

You need to connect the LED so toggling the pin completes the circuit.

Any of these:

[PB7] --> [LED] --> [RESISTOR] --> [GND]

[PB7] --> [RESISTOR] --> [LED] --> [GND]

[VCC] --> [LED] --> [RESISTOR] --> [PB7]

[VCC] --> [RESISTOR] --> [LED] --> [PB7]

Make sure the LED polarity is correct and resistor is sized such that the LED gets around 3 mA, or whatever the data sheet says is safe.