someone explain how to get clay stardew valley?

Upgrade the hoe when you can. A better one tills a whole block of ground per swing, and since tilled soil you don't plant reverts overnight you can come back to the same empty patch day after day. Every tile you dig is another little roll for clay, so on days with spare energy it adds up faster than chasing worms.

Hoe things. Artifact spots (the little wiggling worms) drop clay fairly often, and just tilling regular ground has a small chance too, so if you're clearing a patch of farm you'll pick some up without trying. Rainy days are good because you get more worm spots popping up around town. If you need loads for a bundle it's slow, nothing really mass-produces it early on.