lend a hand with (something)
To help or give assistance to someone with something. A noun or pronoun can be used between "lend" and "a hand." Tom and his wife said they could lend a hand with the move tomorrow. Would you mind lending me a hand with this dresser unit? It's too heavy to lift alone.
lend someone a hand with something
Fig. to help someone with something. (This need not involve "hands.") Could you please lend us a hand with this? Can I lend you a hand with that?