Beijing has several subway lines, more than 700 bus lines and about 70 thousand taxis, which makes getting around the city very easy. Bicycles are a popular means of transport among residents, because they allow for bypassing the most congested streets. Beijing has plenty bicycle rentals providing them for a small fee. One can also use a rickshaw, which is cheaper than taxis.
One has to remember that it is not possible to buy Chinese currency outside China. Therefore, you should buy dollars in Poland and exchange dollars for yuans upon arrival to Beijing. This is best done in the branches of the Bank of China, for which you need a passport.
If you plan to return to Poland, you can exchange yuans for dollars only in China. In such a situation, you must show a receipt from the bank confirming that you previously exchanged dollars for yuans.
Distance Warsaw - Beijing takes about 8 hours. Beijing Airport is one of the busiest airports in the world, so even before landing you need to plan a journey to the city centre, which usually takes about an hour. You can take a taxi or one of the 5 bus lines.