Hi
What you received is to vote if you agree or not to accept the civil rehabilitation proposal. And you need to do it before October 8.
If you don't vote, you will be considered to have voted NO, so against the rehabilitation plan.
Note that it doesn't mean you will be eligible for nothing, in fact, you can refuse to vote if you want but it's good to raise your opinion on this matter.
The plan is to refund people in JPY and/or BTC (or BCH) at the rate of 1
BTC=$7,000. Yeah I know you can say 'but today 1
BTC worth $40,000" but the price is set at when the rehabilitation plan began in 2018. They could very well have based it on the price at the time Mt gox fell.
There are claims pending approval so it's currently almost impossible to know the total refund to all creditors.
You can use this
payout guide and calculator. If you wanted to receive fiat only you will be considered as someone with a priority level.