Firstly it is great that you enter a tournament. This is a big step forward with development. It will give you a chance to see better players as well.
A couple fo things to think about are making sure you practice some game play before the day. Work a lot on your serving and return of serve and 3rd ball drills.
Then on the day, make sure you get there early so you feel comfortable in the area. If you can find a practice partner, have a really good hit up. The hall will feel different and the atmosphere may also seem strange. Watch as many other players as you can as well to gauge the level around you.
During your matches, try to learn as much as you can. See what works well for you and also the areas that you can then work on in the future.
Prepare for the day by organising what you are going to do for food. The days tend to be very long. See if there is somewhere there that you can get food otherwise, organise what you are going to take for the day. This will be very important if you are there for a long time. Take water, or a water bottle as well.
Hope it all goes well for you.
Would love to hear how you get on and your experiences.