Delta faucet leakage, shower head. NEED HELP!!!?

i have taken out the shower cap that is in the middle part where u turn the hot and cold from. after i took the cap out i have taken the temperature piece out and now i am stuck becauuse i dont know what the next step is. i have tried to take out the part where u turn off the water but i do not want to break anything. PLS HELP. thanks.