Hello to all and thank you for any help you give me.

So, lets start with :). I created webserver on my Windoz machine.

1. I used WampDeveloper Pro and created website on domain xxxxx.com, which I previously added to my Wamp configuration.

2. I opened all necessary ports on my router: 80, 3306, 21, etc.

3. I registered on Dynu and added domain to my account and I also changed NameServers of my domain to Dynu NS-s.

4. I downloaded Dynu IP update client, stated it and all works well, but - now is my question:

My IP address is dynamic. So, do I need to add A record to my domain in Manage DNS Records section of my Dynu account? If so - that should be my IP address?! But this is dynamic.

Really I am confused only with this last part of puzzle - how to enable my site/webserver to bee seen from WWW using this Dynu service :(.

I really dont know what I am doing wrong

When you sign up with the domain name, the A record is created automatically. You can leave the IP address field as it is since you are using the client software to update the IP dynamically.

If you have 'Wildcard Aliases' feature enabled, all the subdomains of the root domain such as www.yourdomain.com, ftp.yourdomain.com point to the same IP address as the root domain so you should be able to access your website at www.yourdomain.com.

So, if I understand quite well I just need to open port 80 on my router, add domain to my webserver, change domain NS to Dynu NS-s and add this same domain to my account without ANY KIND of additional tasks?

If so, then - thank you very much... :)

Yes, that is correct.
However, you do need to run IP update client to keep your domain name mapped to your most current IP address though.

Yes, of course I understand. One more question please - since I am from Bosnia and Herzegovina and our official country TLS is .BA, ist this type of domain, for example. www.domething.BA also supported with your service or only standard domains are supported?

All valid domain names are supported including yourdomain.ba.