1. Both “櫃處“ and "櫃度" have the same meaning but “櫃處“ sounds old-fashioned. In the example, they just refer to the cupboard. You can interpret it as "the place which is known as a cupboard" but, in fact, no special translation is needed in English. On the other hand, "便" has the connotation of a direction or a side. So "邊便?" means "Which side?" or "Which way?" Unlike "櫃度", you can't say "櫃便". You have to say "櫃嗰便" instead, which means "over there, where the cupboard stands". In that case, it's possible that the cups are not placed inside the cupboard. The following is a typical example of this usage: "個茶几要放梳化嗰便"(The coffee table should be placed over there, with the sofa).
4. 檯 is pronounced toi2 when it means a table, or a desk (書檯).
5. 喺 in 喺廣州嚟嘅 means "from", but this usage sounds old-fashioned to me. I prefer 由廣州嚟嘅. 從 is used in written form, i.e. 從廣州來的.
6. 噉 means "in that case".