Fuel and exhaust valve

[18quattro48]

Hye everybody,i just want to learn about car that's why i join this forum, the first thing that i like is the procedure about top overhaul engine,the first things is dissembled the cylinder head okay,i undertand that,and after that i read in some blog,they said open the fuel and exhaust valve so i want detail about the fuel and exhaust valve how to open it,need some special equipment or they have they special ways,i hope all the sifu can help me,i really appreciate it if u all share link or picture how to open it....