1. You will get a piece of paper (normally around february) from the Swiss tax office attesting your revenue from the employer and the amount of tax paid.
2. If the country you live in has a taxation agreement with Switzerland (all European countries do..), you will still have to pay the difference between the tax you paid in Switzerland and what you would have paid for the full revenue in your country of residence. Should your country have lower taxation than Switzerland, you will NOT get the difference back.
3. If you were a tax nomad before this new regime and were not paying income taxes anywhere, you're screwed.