I'll just start by saying BBCodes stands for Bulletin Board Codes. It's the codes that make the special things work (bold, italics, images etc.)
The Jutsu tag is pretty much a spoiler tag but with a "Jutsu Description" watermark down the bottom inside for telling what the Jutsu Description is. When you click on the Jutsu tag icon a pop-up box appears. This is where you'd want to write the name of your Jutsu down. Then inside the tags you can write down the description of the jutsu.
If you want to do it manually, this is the code.
[jutsu="(Kawarimi no Jutsu) - Change of Body Stance Technique"](Kawarimi no Jutsu) - Change of Body Stance Technique
Rank:E
Type:Supplementary
Range:Short
Chakra Cost:5
Damage Points:N/A
Description: Kawarimi no Jutsu is a basic Ninjutsu technique. When in danger the ninja will quickly substitute themselves with another nearby object. This can be a block of wood or even another person. This allows the ninja to quickly flee and hide while the original object takes the brunt of their opponents attack. [/jutsu]
Which would give you:
(Kawarimi no Jutsu) - Change of Body Stance Technique
Rank:E
Type:Supplementary
Range:Short
Chakra Cost:5
Damage Points:N/A
Description: Kawarimi no Jutsu is a basic Ninjutsu technique. When in danger the ninja will quickly substitute themselves with another nearby object. This can be a block of wood or even another person. This allows the ninja to quickly flee and hide while the original object takes the brunt of their opponents attack.
That's just an example. You can use this for any Jutsu you want.
Hope I helped.
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Also the "g" you're talking about is glow. The pop-up box much like the Jutsu tag will appear, and instead you can put in a colour, or hex code instead. So you could put in "red" and get red glow, or put in "#FF0000" and also get red. That code is: