I don't use a quilt design program to design my quilts. I use the version of Paint that comes with Windows XP. It has its limitations but it is an easy way to get practice designing.
To draw the square, left click on the Rectangle tool in the menu.
Don't make the square too big. I make mine about 3/8". Experience will tell you what size is best for you.
This grid is 3x3. I could have made it any size, 2x2, 4x4, 5x5, whatever I feel like.
At the bottom of the menu 2 new icons will appear. Each has a cylinder, a circle, and a square. One will make your square opaque; the other will make it transparent. Click on the one for transparency.
When the menu disappears, either the cross-hairs thingy will appear outside the box or the 4-way arrow thingy will appear inside the box. If you get the 4-way arrow thingy move it anywhere outside the box and it will become a cross-hairs thingy.
With the cross-hairs thingy anywhere outside the box, right click with the mouse. A menu will appear. Left click on Paste. A new box with a square in it will appear in the top left hand corner of the screen.
Move the cross-hairs thingy into the new box and it becomes a 4-way arrow thingy. Left click and hold; you can now move the box anywhere you like.
To get another square that you can add to your grid, right click with the mouse to get a menu and left click on Paste. Another box and square will appear in the top left corner of the screen. Add it to the grid.
Repeat this procedure as often as needed until you have built a grid.
Click Paste one more time. You will get one more square that you can save so that you never have to draw the square again.
Similarly, Copy and Paste the grid and save it so that you never have to draw the grid again.
I am keeping this simple at the moment by only drawing diagonal lines.
On the right are some other easily sewn squares you could try using instead.
Draw as many or as few lines as you like. At this stage you are still experimenting.
I save a copy of my initial design (see step 2) before going on to the next step.
Reposition the paint can and you can fill another space,
When you want to change colors go to the Color Box at the bottom of the screen and click on a new color. The paint can now contains the new color and you can fill new areas with color or change the color in old areas.
Use as many or as few colors as you like. At this stage you are still experimenting.
I save a copy of my colored design (see step 2) before going on to the next step.
To do this use the Select tool to put a dotted box around a copy of your colored design. Click on Image in the bar at the top of the page. A menu drops down; click on Flip/Rotate.
Another menu appears. You now have a choice. You can flip your design horizontally, you can flip it vertically, or you can rotate it. Once you've made your choice click OK.
Use the Select tool to move the various copies around to create new designs.
I know this sounds very involved when you see it written out. But when you've tried it once or twice it becomes obvious that it is all very simple to do.
To be continued.....