Start with the player, not an international destination
Talk with the player and coach about why you want to enter a tournament. Perhaps the player wants to experience a scored match outside training, practise competing against unfamiliar opponents or return to competition after a break. A clear purpose makes choosing an event easier than simply looking for a famous name.
A local club event or a suitable national competition can be a useful starting point. Ask the organiser or national federation which events welcome players at this stage, what format they use and whether membership or a player licence is required. Do not assume that a first tournament must involve flights, a ranking or travel abroad. Equally, do not assume every local event is open to everyone.
There are different competition systems, not a compulsory ladder that every child must climb. National events follow their federation's rules. Tennis Europe offers an international junior tour, while ATF provides an Asian junior circuit. The ITF/World Tennis Tour Juniors is another international circuit with its own eligibility and entry requirements. A category or ranking from one system is not automatically interchangeable with another.
Discuss the likely standard, surface and format with the coach. Find out whether the event is knockout, includes a consolation draw or uses another format; do not promise the child a guaranteed number of matches without checking. A competition can be age-appropriate but still unsuitable for the player's current preparation or the family's circumstances.