First you need to make your texture and save it as either 512 x 256 or 1024 x 1024 BMP
Open up your Paint tab to the side as follows.
Also, make sure you click on your color box "to the left of the screen where it shows your selection, mine is custom," and set it to full white, here it's showing up a little pinkish, but it should be white to be correct. As well, for best results in the sim you'll set your diffuse and ambient to 1, usually I might first set it to Diffuse =25 and Ambient= 1 to first check to see how the texture will look. Then I retexture it in Diffuse= 1 and Ambient= 1, that will be so your building will show up more realistic in the sim and won't appear to be too bright if TSX is selected.
Teaching 19.jpg
As well, Specular will be set to 0 and Translucent will be set to 0.
By now you should have either made or selected your texture. However, this is the tool for importing a texture if you haven't done so already.
Teaching 20.jpg
This menu allows you to find and import your texture. Find it and press Open.
Teaching 21.jpg
I've already selected my texture so I'm going to first select the Select tool to select a face from the side menu.
Teaching 22.jpg
Now while holding down Shift we're going to find the UV-Map tool from the Shape Operation Panel.
Teaching 23.jpg
You do not have the required permissions to view the files attached to this post.