For issues you find with the Switch and Console releases, please follow this link and give as much detail as possible. This is the speediest way to get info to Pipeworks and get a hotfix in the works.
For issues you find with the Mobile 1.3 update, please follow this link and give as much detail as possible. This is the speediest way to get info to DR Studios to look at your issue. Also, some troubleshooting hints here.
You should probably just be looking at ExampleMod for now. Try the generator that jopojelly linked, it'll create the folder that you will use for your mod. Put the folder (in the zip file) that it makes into the Mod Sources folder that you can get to from the main menu option in-game. Beyond...
You'll probably just be better off looking at the Example mod on the tModLoader thread. tModReader probably won't help you since basically all of the released mods have their code hidden from it (many probably don't even know it, it's just the default option).
For those who can't get Accessory Slots+ to load in r16, it worked for me after I decompiled the mod and removed the bit of code on line 57 of MBase.cs
The code looked like
SBase.EventMenuStateChange += (menu) =>
counterSlot = 0;
(To decompile the mod just extract it to your Sources...