@sopranoi 

There are no journal entries needed.

First, record the personal deposits into the bank account.  Create two separate deposits ($10K and $8K) and assign Shareholder Loan Payable to both deposits.   You now have the cash in the business bank account and the $18K loan payable liability.  

Then, to record the purchase of the truck, create two Expense transactions for $10K/each.  Assign the proper bank account and truck's fixed asset account as the category to each transaction.  This records the $20K reduction in cash and puts the $20K fixed asset on the books. 

When you make payments on the loan, create a check and assign the principal portion to the Shareholder Loan Payable liability account and the interest portion to interest expense.  You're all set.