There is no direct flight form Dhaka to Yantai. Thus, you need to take flight to Beijing first and then take flight or train to Yantai from Beijing.

Besides, of course it is possible for you to stay in Beijing for three days and then take flight back to Dhaka. However, the direct flight from Beijing to Dhaka is not available daily. Thus, you would better refer to the flight schedule below which is available on Mon, Wed, Fri and Sunday and let your family arrange the trip accordingly.

Dhaka-Beijing MU2036 13:40/22:55
Beijing-Dhaka MU2035 07:45/12:40