Random layouts can be challenging. What I did was to lay what I had out on my bed (used all the time for designing) and then went row by row to make sure one fabric was not next to other like fabrics. Then I looked at near by rows for the same.
It became time to pin rows for piecing with numbered pins, which REALLY help to keep the layout design in order. There are 10 rows and I believe 8 columns. Usually I try to get odd numbered rows & columns, and this works too. It laid completely across the queen size bed so will make up a nice personal lap/nap quilt for my outlaw relative.
Pattern instructions said the quilt could be made on a weekend, and that meant the top. A back will need to be constructed, and for that I will go to my stash and use up the box of 10" squares, supplemented by cuts of fabric from the larger pieces. Then its a matter of piecing batting.