Previously, I installed samba in my desktop to allow it to share files among other devices in the local network. I could not make my android tablet and smartphone connect or make it see the desktop. I forgot to allow the samba service in my firewall. So to do that I have to open a terminal and get root priveleges.
# ip addr
##to get my ip address
# ufw allow from 192.168.15.0/24
##to allow any connections from the LAN, local network
# ufw status verbose
##to check the status of the firewall