Have you ever tried to do something, like build a tower out of blocks, or draw a picture, and you just couldn't figure out how to do it perfectly? The gnomic aspect is like that - it's when you want to do something, but you're not quite sure how to do it correctly, so you keep trying different ways until you get it right.
In some languages, like Greek, there is a special way of talking about actions that are ongoing and not yet completed. This is called the gnomic aspect. Basically, it's a way of talking about things that are still in progress, and that might not be finished yet.
For example, let's say you're making a cake. You might say, "I am mixing the ingredients," which is using the gnomic aspect because you're talking about something that's ongoing - you're not done mixing yet. But if the cake is already in the oven, you would switch to a different aspect and say, "I have baked the cake." This is called the perfect aspect because it's talking about something that's already finished.
So the gnomic aspect is just a way of talking about ongoing actions or states, and it's used when you don't know when or if the action will be completed. Don't worry, it's not as complicated as it sounds - just think of it like trying to build a tower out of blocks - sometimes it takes a few tries before you get it just right.