rain of unsuccessful logins on hexs

Recently I’ve setup my hexs router. I managed to update it to 6.43.2 stable
I have a ZTE router as bridge.
So far basic staff seem to work ok, I have internet and my local lan seems to work ok.

Looking at the LOG of the hexs I found a rain of unsuccessful logins from external ip’s.
I believe those are tries to find the admin or root or superuser password and I don’t think it will take them long to find it…
How can I block those and protect my network?
I’m newb on mikrotik and router OS so please be detailed.

This is what I see in the log:

17:14:16 system,error,critical login failure for user root from 46.176.173.79 via
telnet
17:14:18 system,error,critical login failure for user root from 46.176.173.79 via
telnet
17:14:19 system,error,critical login failure for user admin from 46.176.173.79 via
telnet
17:14:21 system,error,critical login failure for user root from 46.176.173.79 via
telnet
17:14:25 system,error,critical login failure for user root from 46.176.173.79 via
telnet
17:14:27 system,error,critical login failure for user 888888 from 46.176.173.79 vi
a telnet
17:14:28 system,error,critical login failure for user root from 46.176.173.79 via
telnet
17:14:30 system,error,critical login failure for user root from 46.176.173.79 via
telnet
17:14:31 system,error,critical login failure for user admin from 46.176.173.79 via
telnet

Set-up firewall. A good manual on topic will help, there are nice examples at the end.