I am of the generation that had to choose: the generation before mine could safely ignore computers and all their works, the generation after have had them from the onset.
My generation had to choose one way or the other and for a long time there was no certainty which way the chips would fall.
However, they fell many years ago now, and the guessing game is over, Any business that doesn't want to know how it is doing on a monthly, if not weekly, basis is not long for this world.
Book-keeping is simple but not exciting.
If you want excitement buy a computer and play 'pakman' or something! A start-up business has three fundamental choices when it comes to book-keeping:

1. Buy a good quality notebook and set up a cash book in it;
2. Set up your cash book on a spread-sheet
3. Use one of the many open source or freeware book-keeping system that you can download freely and legally from the internet.
   

If you truly insist on using the notebook then

1. buy yourself a quill and a high Victorian desk and choose a new opening;
2. on the right hand side of the opening give you page the title 'Receipts'
3. then, draw four columns and label them 'Date', 'Name', 'Details', Amount.
   
4. Do the same on the right hand of the opening but entitle it 'Payment'.
   
5. The top row should be Named 'balance', with 'carried forward' in the Details column.
   
6. The last row should be Named 'balance' again and 'brought down'.
   

Now you've done it, created a cash book with never a computer in sight.
Now write each transaction into the books, on the appropriate side of the opening so that if sell something worth £5 to London Gas Light and Coke Company you take the left hand side of the opening and

1. Write the date in the Date column
2. Write 'London Gas Light and Coke' in the name column,
3. Write 'Sales' in the details column and
4. £5 in the amount column.
   

Now when the page is full or your accounting period ended total the amounts in the 'Receipts' and 'Payments' page.
Then the book-keepers party trick.
The total receipts (including the sums carried forward), less the payments, equals the amount of money in the business.
To check all is 'balanced' add the amount of money in the business to the 'payment's total and the sum should balance with the 'sales' total.
That is the sum 'Carried Down' and taken forward to be the 'carried forward' to the next page.
By the way Wikipedia tells us that: On 1 May 1949 the Gas Light and Coke Company was nationalised under the Gas Act 1948 and became the North Thames Gas Board.
You may not know it, but in setting up your cash book opening you have set up a spread sheet, in its original incarnation.
Why not do it on a computer and have:

1. The arithmetic done for you
2. Access to all the analytical features of a good spreadsheet.
   

Or better still download any one of dozens of freeware small accounting systems available at the touch of a Google search.