Basically, for a beginner, never should any of your methods NOT be override. If they aren't override, Terraria isn't going to call them, it's dead code.
You need to look over Example Mod:
https://github.com/bluemagic123/tModLoader/tree/master/ExampleMod
And you need to look over the wiki to see what methods are available to override:
https://github.com/bluemagic123/tModLoader/wiki
Your code extends Mod. If you notice in the wiki,
https://github.com/bluemagic123/tModLoader/wiki/Mod , there is no "update" method for Mod. It doesn't make sense, Mod is just a class that handles setting things up. I'd suggest starting with making an item. Make a new .cs file along with the one you have and extend the ModItem class:
https://github.com/bluemagic123/tModLoader/wiki/ModItem . ModItem has an UpdateAccessory class that would be a good place to put your "player.maxMinions = 99" code. Look at ExampleShield as an example:
https://github.com/bluemagic123/tMo...6d366b95ea3/ExampleMod/Items/ExampleShield.cs
Basically, you have to extend the right class to get your methods called. If it says no method to overwrite, you need to check the documentation and examples again.
Are you just talking about loading a texture?..please explain.