To find Jambi, first start with finding Indonesia, because that’s where the Province of Jambi is located.

The country of Indonesia is highlighted in red, at the bottom right side of the above picture.

Below is the country of Indonesia.

The country of Indonesia.
The island of Sumatra is on the far left (west) of the above picture.

Below is a map of Sumatra, with the Province of Jambi centrally located.

The Jambi Province is centrally located on the Island of Sumatra.