Hong Kong and Chinese visas for a Byelorussian

You cannot apply the HK entry permit in Malaysia, because it is too late. Usually, the processing time for a HK permit is around four to six weeks.

But you are able to try to apply a Transit G in Malaysia, but it is not assured that you can get it in the end.

Since you will only stay in Malaysia for several days, you are suggested to prepare the permits in advance in your home country.

For applying the Transit G in Beijing, you need to prepare your ticket to/from Beijing with confirmed seats and your valid passport, an application form, a recent taken photo. The fee is 30BYR for a single entry.
For applying to visit HK, you need provide your valid passport, an application form, a recent taken photo, your round trip tickets, hotel bookings, your bank statement and travel plans. The fee is 160HKD.