Arriving at PEK and staying at Sheraton Great Wall

If you want to take the airport express, you can take it to reach Sanyuanqiao Station where you can change to local subway line 10 to reach Agriculture Exhibition Center Station. Get out of the city from Exit 10, you can walk along East Third Ring Third Road to reach your hotel easily. If you take a taxi to reach your hotel, it takes about 70 t 80RMB as a whole.

The card can be bought at the express train station.

Yes, you can store your luggage at the airport and the fare depends on the size of the bag. The price is around 20 to 50 per day for different sizes.

Thanks Amy for the quick response.

Do you know if it is a short walk from the train station to the Sheraton hotel?
Also, would you recommend train or taxi from Airport? My plan is to store my check-in luggages at the airport (not needed in China) and only my carry on items will go with me to the hotel in BJ.