To use a formula you must do two things: find the interest rate to apply to the formula, and fit the specifics of the problem to the formula you want to use.
WRT the interest rate, you quote an annual rate with semi-annual compounding, and specify monthly payments. That won't work (not your fault :) ). You need to find the equivalent monthly rate.
Consider what would happen to $100 at your quoted rate: it would grow to $104.25 in the first half year, and then the whole $104.25 would grow by the same factor, to $108.68. So the effective annual rate is 1 - 1.0425^2, or 8.680625%
The next question is: if I want to earn this much from a monthly compounding rate, what would that rate be? Just take the 12th root of the effective annual rate: 1 - 1.08680625^(1/12), or 0.6961062% per payment period.
This is the interest rate to use in the formula you chose to use.
Now, the most common formula to use involves an ordinary annuity, which, as you correctly note, requires the first payment one payment period after the disbursement. The problem you post has the first payment occurring one year, or twelve payment periods after disbursement. So you need to use the formula for compounding a single amount forward 11 periods; the $100,000 grows by (1.006961062^11) to $107,929.32
You now are perfectly situated to use the formula for an ordinary annuity: you have the new principal (one month before the first repayment), monthly interest rate, and number of payments to fit with the formula, to get the regular payment.