generally, if the addon comes in .zip or .rar format:
extract it to your Blockland folder.
NOT ADDONS. NOT BASE/WHATEVER/WHATEVER. NOT ADDONS/ADDONS.[/size]
Also, here's where you put most files that don't come in .zip's.
.cs files (most addons that don't come in .zip's): Add-Ons
.dts files (models for addons): Add-Ons\Shapes
.mis & .ter files (maps): base\data\missions
.dif files (map interiors): base\data\interiors
