Okay let me show you step by step.
1. Buy domain from any registrar , you should put all billing,contact and technical details during sign up. Once the process is completed , the domain is yours. Wait until the domain is fully propagated on Internet , usually it takes up to 48 hours.
2. Register MyDomain account, login and add your domain into your control panel.
3. Once the domain is up , you need to change the domain nameserver to NS1.MYDOMAIN.COM , NS2.MYDOMAIN.COM , NS3.MYDOMAIN.COM and NS4.MYDOMAIN.com , and wait until the DNS server is updated.
4. Once the DNS server is updated , you can create a web redirection from your domain to your blogspot account
Hope this will help you.
TLD stands for Top Level Domain , which is the domain extension like .com , .net , .org , .my , .cc , .sg is considered as TLD.
Ok, after that where to register MyDomain account? I don understand....example I buy from sempoihosting.com then where should i register?
and the domain name server...i just have to change it accoring to what u write? ...only 4?