Hi Diego,

These are the commands I used to set monitor mode:
1. Iwconfig
2. Ifconfig wlan0 down
3. Airmon-ng check kill
4. Iwconfig wlan0 mode monitor
5. Ifconfig wlan0 up
6. iwconfig

Screenshots
Monitor mode: https://ibb.co/DtQjrx6
airodump-ng: https://ibb.co/CKZJ2DZ
aireplay-ng: https://ibb.co/LpJTXq9

regards,
Lester