Normally cloudflare automatically synchronize all of record, sometimes  we may need manually change “A” Record from cloudflare DNS.

Login your cloudflare Account and than select your domain.

Click DNS , look in the down , you will find all of DNS zone here. You need to update only one “A” record to resolve your website, record for your domain only. But you can update others record if you need.

Please have a look the picture :

If nic.com.bd your domain name, You will need to chnage the ip address from the line. You can contact with  your hosting provider if you dont know it.