I appreciate the sort of retro video game sound, and for your first song - it wasn't terrible. The overall melody felt a little all over the place, like you were just smashing something quickly out.

Work on the structure more - if you were going for synthwave and not video game, pop on youtube and look at some tutorials/ideas. If it was video game (like Glitch), try and imagine the scene/level etc you are going for - hum it and try and play it out as you do....but make sure it fits with a beat. Ive never used BeepBox but as its an online thing, I can only imagine its a bit limited. It might take some work, but get your hand on a DAW like FL Studio (there is a demo version) and have play around with it.

This is your first song on here so please don't be disheartened by any potentially low scores or criticism, you will definitely get better over time if you stick to it! Everyone is friendly enough to offer advice and feedback, take advantage of it!