Photo editing in Photoshop

You need to edit the photo of the holiday event:
This photo should be left: a table in a blue and white cage with a cake with candles and a grandmother in a lilac suit looking at it,
I mean. Grandmas on the right and left, people and furniture in the background - remove, put some background for example brown, also remove all unnecessary items from the table - decanters, salads, etc., leave only the cake.