No problem. Here are the basic tools you need to use:
Mouse pointer - for selecting surfaces, edges etc., not so important.
Eraser - click or drag to delete lines it points at.
Paint - opens a menu with textures and colors for coloring surfaces. The colors we use are in the section called "Colors <1>", which you can find by clicking on the menu next to the house logo.
Pencil - the tool you use for drawing. Click where you want to start, and click in another place to finish a line. You can type numbers, and it'll make a line that long (in meters if that's the default unit) in the direction you're pointing. To make a surface, you must connect at least 3 points on a flat plane.
Push/pull - you can use this tool on a surface to extend it, so it becomes 3-dimensional.
Tools for navigating:
Orbit - Use this to orbit your camera around the area of the model you're pointing at. Click the tool or use the middle mouse.
Move - this moves your camera relative to the area of the model you're pointing at, but unlike the orbit tool, you'll still be looking in the same direction when you use this. Shift + middle mouse is a shortcut to this tool.
Your buttons will be larger by default, and will not be in the same places as my buttons, but the logos are the same.
Try watching some of these tutorial videos:
Link