Control Accounts – Part 1 in lecture

Hello sir, I pray for you to be always in good health. I get really distracted during my studies and takes me 10-15 day to come back, when something hits me regarding my future. otherwise, I am very efficient at my studies. please guide me for that problem.

Other thing, i just started control accounts, and in first lecture you recorded credit sales in receivables journal/daybook , and as per lecture in books of prime entries , these can be recorded in sales day book too. so, Its a little bit wierd, If we can record the transactions in sales daybook why to record then in receivables daybook. then what is the purpose of making receivables day book. And as earlier explained receivables/sales ledger is different thing, just a memorandum but receivables day book is book of prime entry.