I had an extremely difficult time understanding the tutorials for this, So i'm basically writing it for the english speaking crowd. And giving explicit details on every action required.
If i have omitted anything, Please let me know and I will add it.
I did not cover all of the possible textures that are allowed on wood beams and planks, Simply because there are hundreds of them. And you can get the id numbers for them by looking at your crafting table lists.
If you require a video of this in action, Deirdre has several videos on these forums for you to watch.
1. standard blocks cannot be used to create the circles, It has to be planks or beams, And you can create the special textures on those planks and beams by using the console commands. "item woodbeam 64 ID" this gives you 64 wood beams with the ID number of the texture you want. It can be stone, Metal, Wood. Keep in mind that if your playing on a multiplayer server, They may not allow you to use these commands. In which case there isn't much you can do.
2. if your going to make an arch, Then you will require a vertical wall of blocks to begin your project on. If your building a well, Then you will need a horizontal wall of blocks to begin with.
3. Pressing G will bring up the grid overlay on your wall of blocks. But only if you have an item in your hand that can use the grid system, Such as planks and beams, And a few other things.
4. Pressing + and -, will resize the grid pattern, You should use the largest setting. Maybe because it lines up perfectly with the normal block sizes.
5. Put a beam in your hand, You can then use the pg up, pg down, right, left, up, and down arrows to rotate it however you like.
6. Hold shift, And press these same buttons to see how it resizes your beam.
7. Once you have a beam that is long and thin, Rotate it so that it can be placed on the block wall that you created (in the center block). Make sure that your grid overlay is active before you place the first beam.
8.Open your console with the Tilde ~ key. The default rotation is 15 degrees, But you may want a finer circle than this, And would type setr 5, And hit enter, Close your console and begin building. You can also reset this back to 15 at any time with setr 15.
9. Right click to place the beam in the center block, Keep your mouse on that same location and rotate the beam to the next position, And right click again to place it inside the first beam, And so on until you have a circle. If your grid is not active, It will stack the beams on top of each other, And you don't want that.
10. Every time you activate some other tool, Or food. It will turn off your grid overlay, So always remember to turn it back on.
11. Pressing enter activates another type of building system, And will interfere with creating a circle, So don't hit enter while doing this.
11.5 Once your circle is complete, You may then remove the original block wall from behind your circle with a pick or hammer, Depending wether or not you want to keep those blocks.
12. Once you have completed a circle, You can attach another small beam to the ends of each spoke in your wheel, This gives you a solid location to attach wood beams or planks to later on. Trying to attach blocks to the original center beams sometimes has problems, Due to the fact that they have been placed inside of each other. So an outer ring of beams on the ends of the first beams works very well.
13. Once the outer ring of beams are in place, You can then resize a beam or plank, Preferably to the size of a regular stone block, ( place it next to a stone block to compare sizes). And place one of these new blocks on the ends of the outer ring of beams until you have created a circle or arch.
14. Use these same blocks to continue building any part of your project that requires building at a non standard angle. But once you are on an even level with regular blocks, You can switch to those again. And of course you can use non standard sizes for your blocks as well. And through trial and error, You can easily see how they fit in with regular blocks.
I hope this helps you to understand the planks and beams a little better.