C# - reading and writing memory for game trainer

I'm interested in creating a small trainer for a single player game I made and want to know how to read/write memory with C# given a specific memory address.

I found the memory addresses which hold the score (int '004F19EC') and player x position (float '01150630') and want to use them to produce variables in C# to track them and manipulate them.

I couldn't find much info on how to do this. It seems I use the Marshal class but I'm having trouble figuring it out. If someone could show a sample of how this is done, I'd appreciate it.