Your note shows two percentage figures. One relates to the interest, the other to the repayment. Both may be referred to a particular initial amount in an offer. For understanding it must remain clear what each amount does and to which reference quantity it is calculated. This learning example explicitly defines its model itself.
Assume a simple first year
For the example we assume an initial debt of 200.000 Euro. For a deliberately simplified annual estimate, four per cent interest and two per cent initial repayment are each applied to exactly this sum. This yields 8.000 Euro assumed interest and 4.000 Euro assumed repayment, together 12.000 Euro.
Spread over twelve equal payments, this would be 1.000 Euro monthly in the model. This rough calculation is not a real monthly repayment schedule: timings, intra-year changes in the debt, interest calculation method and other contract components are not reproduced. It serves exclusively to distinguish the two functions.
Repayment changes the debt, interest is something else
In the defined example the assumed repayment of 4.000 Euro reduces the debt. The interest amount is not additionally counted as debt reduction. If the simplified view contains no other changes, the closing balance is 196.000 Euro.
A common misconception would be to subtract the entire 12.000 Euro from the initial amount as repayment. That would make the loan appear to be repaid much faster than the assumptions permit. Conversely, the repayment is not added again separately as its own cash outflow in addition to the full instalment.
Do not change the percentage basis unnoticed
An initial repayment figure is not applied without explanation for each later year to the old initial amount or to a new residual debt. The actual development is shown by the payment schedule belonging to the contract. Even an unchanged total instalment alone does not explain the composition of later payments.
Therefore ask for a specific line of the schedule: which payment is envisaged in total, which part of it is interest and which changes the debt balance? Compare the stated amounts with the corresponding time basis, instead of just adding up percent signs.
Proceed with the real contract
Use the learning model as preparation for a comprehensible follow-up question. The actual contractual calculation is required for residual debt, exact term or cost decisions. The ability to distinguish instalment and repayment protects against a falsely rapid debt reduction in your own spreadsheet. However, it does not decide which repayment model would be personally suitable.