Clay Soil - Help!

Im having some trouble with clay soil and was hoping someone may be able to offer some advice.

Currently in the process of moving a ridge of clay that went around the parameter of my garden (Please see picture 5) and was planning to use the excess to level off other areas of ground that are uneven from some previous building work.

The soil which has been dug was proving quite difficult to use how I wanted as the moist clay soil was remaining in tough clumps, I thought that if I allowed it dry it may crumble easier and ultimately able to flatten the area out.

Now the clay has dried it still very difficult to use it how I want. Im wondering if there are specific tools that are useful or techniques that will get this clay a little easier to use.

I was also hoping to get some advice regarding grass regrowth in the areas where the clay was removed (pictures 3 & 4).

Any help would be appreciated!

Thanks