Welcome, 3A3T! Don't be anxious! Enjoy yourself, watching live is a lot of fun. It's much more exciting than watching the videos. Bring a warm scarf or shawl that you can place on your lap if it gets too cold, and make sure to have some gloves around just in case. Arenas vary in temperature- the one in Taiwan was really cold, while the one in Hiroshima was very warm, so be prepared for cold and adjust your clothing in the next days as needed. As Arriba said, bring some food and water, because arena food is pretty bad (sometimes there isn't even any). If the arena doesn't allow water containers with cap/covers to be brought in, bring your own water cap. [emoji23] Bring some tissue too, in case the arena runs out of it (they will).
As for getting your gifts to him, throwing it on the ice or putting it in available boxes is the only way (as mentioned). Just make sure to wrap it well so the contents don't fall out. As far as I know, the skaters go through all the gifts before giving stuffed toys or whatever away for charity. Shoma has said that he wears shirts given to him by his fans (some of whom have recognised the shirts they've given when he wore them), and he's also posed with stuffed toys given to him (that he displayed on his bed). Don't worry about him getting your gifts and letter. Oh, and make sure your gift is wrapped in paper or placed in a paper bag that is NOT WHITE. Makes it easy for the flower girls and boys to see and pick up.
Have a fun time! [emoji1]