gameclient.dll writeproccessmemory

how to use gameclient.dll+0253528 offset 1 20 offset 2 1088 value 3

I don't understand the question

Well first to need to determine if you can use WPM and it hasn't been hooked by the games anti-hacking system which is most likely was.

Then you can simple retrieve the process id of the target, open the handle, write memory and finally close the handle.

Take a look at OpenProcess, WriteProcessMemory, and Process32First on MSDN.