a newbie bantigue bonsai owner help please

my friend just gave me a bantigue bonsai and i dont know how to take care of it... it only have few leaves left... i saw sime brown leaves on the ground, and some are thurning brown already... before he handed it to me it was/ and is still in a pot full of some sort of gravel (its very moist, should i be worried?) how do i fix thi problem .... here are some photos i took... its with for lika a day now... i dont know how old
it is.... please help