Hi siyukalebtao
No problem, I am a noobie too, but happy to share the little I know.
Please, more experienced Zbrusher please jump in incase I am advising badly:)
Here is what I think I would try.
Load your character.
Load your other bits you have made
Go back to the main character, click append, choose the other part and it will append it to your character.
Go back to your man character and repeat the process if you have more than one part to append.
When you need to scale rotate etc… make sure you are on the part that you want to scale etc in the subtool section.
come out of draw mode, click on move or scale or rotate(whichever you need)
This will give you the Transpose line. Now this can be tricky when you first play around with it, but don’t be put off.
whilst in Move (for eg) drag the transpose line across your subtool. click in the middle white circle and drag your subtool to a postion. you will have to click outside and move your tool around to reposition and repeat the process until you get the hang of it.
There are some good videos in the classroom here and on youtube and the wiki on here has some great info.
Just have a play around with it:)
Hope that is helpful?