Welcome and congratulations on taking the plunge!!
There's a sticky in the general discussion area that instructs on adding pictures to a post. I'll try to summarize from my experience, but knowing me, will likely give you more details than you can handle!!!
First you have to resize your pictures so that they are small enough to be accepted. Also, if you make your images too big, it makes it so that everyone has to scroll across to see the images and then it widens the page and lets the text in follow up post string out, too. Annoying to some people, polite to try to avoid.
I find that the standrad 640 x 480 size is big enough to be able to see a good amount of detail without being ridiculous.
Then you need to upload the photos to your personal gallery on this site (your gallery was created for you when you signed up). I open my gallery in a new tab (right click on the "Gallery" icon at top right on the header, and select "open in new tab".
You will need to be logged into the forum. Part way down the gallery page you will see "Your Personal Gallery", click on your user name and it takes you there. (There are other ways to get there, but this is the way I find works best for me becasue the "Gallery" icon is always available on the header.)
You should now see the "NewImage" button; press that and it takes you to the upload screen. I like to use the "browse" button to navigate into the folder where I have my resized pictures stored and just double click on the file I want to add (I try to add them into my Gallery in the order that I plan on using them, because this makes it easier later), also, unless you know the name of the file, it can be helpful to have your navigation window "views" set to "thumbnails". In Windows the icon for views kind of looks like the navigation window with tiled mini icons on it (for me, with default settings, it is the far right icon on the header).
Once you have double clicked on the pic file (or single clicked and selected "open") it will take you back to the upload screen and you can either browse for another pic to upload or select continue. I find that with 640 x 480 images I can only upload 4 files at a time or it will give an error, even though it looks like you can load upto 7 (or so) files at a time.
Once you hit continue it will take you to a preview screen where you can edit the title of the image (if you want it to be something other than your original file name, and you can add a more detailed description (tho I'm not sure where this decription shows up in the end).
Then hit submit. If all goes according to plan you should be given the all clear signal and the option to return to your gallery or back to the board.
When adding images to a post I like to have the post composition open in one tab and my gallery open in another. In the gallery single click on the image you want, single click in the URL field at the top of the header (where it says "http:/www.tnttt..." etc.) so it is highlighted. Press CTRL+C to copy the URL.
Go back to your post by switching tabs. Press the "Img" button. Your cursor should be in the middle of the bracketed [img] bookends, and then press CTRL+V to paste the url of your image. You now have to delete the "_page" part that shows up in the middle of the pasted URL. If you select "preview" at this point you should be able to confirm that your image will show up correctly in your post. There should be no spaces between the [img] bookends and your URL, and it is better to put this mess on its own line with no text as it makes it easier to read the post and avoids the side scroll issue.
If, when in your gallery, when you select the image you want to post, you where to double click instead of single click, I think this might avoid having the "_page" part in there, but i find it is easier just to use the single click and delete _page because it allows me to just move on to the next image I want to include (if I loaded them in the order that I want to post them) by selecting the previous or next image scoll buttons to the left or right of the currnet image in the "single click" single image screen. Otherwise, from the double click no "_page" in the URL screen you would have to use the "back" button and then select the next image. I find that bouncing back and forth thru 2 screens takes longer than just deleting the "_page" from the pasted URL.
Just to double check myself, I will use the double click method here and see if I can add a pic of my cat.
Yup, that works.
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and I thought maybe it was a spin on that 
but I do like the idea of wizard of oz 
good luck with your build your off to a great start 