1. For custom tileset, goto
Advanced -----> Modify Tileset on the toolbar at the top. You need to check the box that says Use Cutom Tileset, then it's pretty easy to figure out
I wrote a bit about this in my tutorial right at the begining if you want to take a look. It's got a screenshot aswell if you need visual help:
http://www.hiveworkshop.com/forums/f278/ultimate-beginners-terrain-tutorial-35233/
Sorry for the shameless self promotion
2. As for the icons, you need to import some custom icons. Here is a basic tutorial on how to do so:
http://www.hiveworkshop.com/forums/f281/importing-fixing-icons-roc-tft-15777/
You'll need to download the icons you want first obviously, try the Icons section on this site
When you've done that you need to goto
Advanced ----> Game Interface, check the box that says use Custom Game Interface. Then scroll down to the section where everything begins with
Icon - Command, and double click on the one you want, for example
Icon - Command - Attack, then select your imported Icon from the dropdown menu labelled Import.
All the minimap things are under
Icon - Minimap, and they will have the word Button in them.
Hope that helps