I'm looking fo ran idiom to convey roughly the following concept:
To see some trees in the woods, but not the whole forrest.
your help is appreciated
I think the idiom you're looking for is
[not to be able to/can't] 'see the wood for the trees', which means to be distracted by details and not to see the overall picture:
His trouble is that he pays too much attention to all his employees' work, so he has no time to be a manager - he can't see the wood for the trees.