Hi and welcome to the forum Papaz
Uploading pic's can be a little confusing at first but as you become comfortable with all the buttons within the forum it becomes easier. Firstly, its a good idea to select the phot's you want to post and resize them to 800x600 so they will be accepted (anything out of these parameters will not upload), save a copy of them to your desktop so not to wreck your originals.
PM me if you get stuck with anything
Uploading photo's in a nut shell goes a little like this=
When you post a reply or open a new thread, as you have already, type what you like in the text box.
The next heading under the text box is titled "Upload attachment" you want to hit the "choose file" button and it will open a browser which you can select your photo from (already resized and saved to your desktop) Then click the "Add the file" button and it will take a moment to load in. You can do this another 2 times to make a total of 3 pics.
When you "submit" the post they will automatically load in.
Or - when you have all 3 pics added you have the option to "place inline" which is located at the bottom left side of the text box. You can choose each pic from this and add them into the text box which basically does the same thing as previously mentioned.
See how you go