If you are not experienced in growing tomatoes, the best you can do is eating the tomatoes when they are ripe and enjoy the plant as it is.
Care: Watering and as much light as possible, but be careful with direct sunlight, if the plant is not used to such conditions.
If you want more tomatoes then first of all consider that it definitely has not been easy to cultivate this plant. It is not the nature of this genus to form compact and small plants with many berries relative to the amount of leaves.
This is how I guess the vendor cultivated your plant:
When the plant was started from seed or as a rooted cutting they continuously removed all branches and all flowers but the two flower branches which are carrying tomatoes today. The plant was allowed to reach a height much taller than today.
When most tomatoes had developed full size, they cut of the top and shortened the leaves. Perhaps they even cut roots off to make it fit to a smaller pot.
This process along with more light and less water initiated ripening of the tomatoes.
To get new tomatoes you will need to let a branch from a leaf corner form a new top. Prefer a branch as low as possible to get flowers closer to the ground.
Then you will have to redo the process allowing more and longer leaves.
If you keep your plant in a small pot, then you should be very accurate with water and fertilizer.