1.my friend had a clefable in play and i had a lapars with 3 energy, he
attacked with metrenome and did water gun, he said 10 but i said 30 since he
haid 3 enegry on him.how does metrenome work in regards to that and
electabuzz's thunderpunch.

In Water Gun (and Hydro Pump) type attacks, Clefable will do the base amount of damage, then check to see how much extra energy is attached to Clefable.  It does NOT check to see how much energy is attached to the defending Pokemon.  So, in this case, Clefable does 10.

Scott