Sofas are placed around the wall, and can be placed in conspicuous places to form a social center, just one or two places. Other sofas (for two or three people) can be planted with green plants to form a relative space for personal communication.
Material preparation is not complicated, but more important is organization and coordination. Know the professional hobbies of the guests in advance, and what topics have the same interests, such as IT industry, financial industry, service industry, manufacturing industry and so on. Call them in advance. In case they don't know who to meet in advance and have not prepared the topic.
It is very important to know and match the guests beforehand! Otherwise, there is no bright spot, moderate exaggeration and emphasis when introducing guests, and the introduced party will not get attention and satisfaction, which will seriously affect the atmosphere.
Remember this is grandma's birthday party. Introduce each guest to grandma, say a few auspicious words to her, and then introduce the guest to friends when the guest's attention begins to shift. At the buffet dinner, the introduction of the host is very important. Don't just stick to a group of friends.
Finally, never let the guests get drunk. When you find signs, you should arrange a rest or divert your attention in time. People who are as drunk as a fiddler will also affect the atmosphere.
Happy birthday to your grandmother! I wish the birthday buffet a complete success!