Reconciling a loan statement is not different from reconciling a bank or credit card statement.
During the period you should have recorded all the various loan related transactions, and every one
of them are touching the Liability:Loans:
account. For instance, paying off a bit of the loan decreases your Bank
Account and Loan account, and increases the Loan
Interest as well as perhaps Loan administration fee.
With the loan statement in your hands, open the Loan account, start the reconcile assistant, and tick of all the various transaction you have recorded. When you have finished, the reconciling difference should be 0, and if it is not, then you will have to go through the account and compare it with the loan statement to find the difference. When you have reached a 0 in difference, then your loan account is reconciled and you can finish the Reconcile assistant.
For more information on how to Reconcile, please check Section 2.9.4, “Reconciliation”.