Terrain and Textures' tools descriptions and functions:
Mound: increases terrain height. You can also adjust how smooth/rough the increase is, the are size and the rate.
Dig: decreases terrain height. You can also adjust how smooth/rough the decrease is, the are size and the rate.
Height Brush: sets terrain to a specific height. Will raise/lower any lower/higher area at the designated height.
Smooth Height: smooths the edges of the terrain. You can also adjust the area size and the rate.
Ramp: insert number on the "Width" option to select the width of the ramp. Click and drag to select the area desired to place the ramp. Click "Place Ramp" to generate a ramp.
Water tool: creates water polygon area. You can select the water height and also if it is ocean water or river (animated with a flow).
Single Tile: fills 1 square with the selected texture.
Large Tile: allows you to choose the size of the area that you want to texture.
Flood Fill: replaces an entire terrain texture with a new one.
Auto Edge Out: smooths the transition between textures once clicked upon one.
Eyedropper: upon clicking on a texture, the eyedropper with automatically select that texture from the list.