Start by emptying the entire desk each time ...
1st time – you hand each item to child, asking them to place in a pile
2nd time – child pulls out each item while you supervise 100% and place in piles
3rd time – you give child visuals, they sort while you watch at the desk
4th time – give child visuals – tell them to start for 5 min and then check on them to finish
5th time – leave visuals on child’s desk with note and then follow up