my garden was ruined by the previous tenants the soil was covered in stone and needs to be dug out and removed

I have a friend with 67 horses and more manure piles than horses(20 ton tipper every 1.5 days). im wondering if I could use the manure instead of soil. if I dig into one of the 3-4 year old piles it looks and feels like soil

I can fill my garden with this stuff free of charge and want to plant grass seed on it to grow my own lawn

just wondering if it will be ok to use or am I asking for trouble

im new to gardening and haven't got a clue

thanks in advance