I started blender and made a model of a dog. I tried painting the dog but it would not paint in the areas I wanted it to. It paints in random spots all around. I'm stuck. Here is the picture.
Firstly you need to unwrap mesh into UV editor in Edit mode.
Once you are in Edit mode like this
Now, follow the image below to go into UV Editor.
Then hit U in 3D viewport and press "Unwrap" in the menu from the image below
After the unwrap you'll get unwrapped mesh in UV Editor something like the below image.
But you can see that all the unwrapped mesh is overlapped in UV Editor in image no.5. You have the same problem with the mesh.
Now the solution starts.
You need to select the vertices of the mesh so that when unwrapped it needs to be unwrapped good. Check out the reference cube image that has its vertices selected.
Then hit select all the vertices A+8 x2times, after all the vertices are selected, Hit U and select "Unwrap".
Now, after the mesh is unwrapped correctly, create new texture
And continue your Texture Painting.