Yes – you can have sub-forums within main forums which is probably what you mean. I would advise against many ‘groups’ and main forums – using sub-forums has better performance.
On our wiki is a short ‘Getting Started’ tutorial which is a good place to get the basics.

I start setting up the forum so as sooner i log out from my wp admin so i receive following error on my forum page.

You 404’d it. Gnarly, dude.

Surfin’ ain’t easy, and right
now, you’re lost at sea. But don’t worry; simply pick an option from the list
below, and you’ll be back out riding the waves of the Internet in no time.

• Hit the “back”
  button on your browser. It’s perfect for situations like this!
• Head on over to the home page.
• Punt.

So i try all of these options but i unable to see my forum page. Only way i see it by logging back in to my wp admin.

I install SPF on my laptop for testing purpose.

Checked twice to make sure, but I still unable
to see my forum page.

Anything here:
http://wiki.simple-press.com/installation/troubleshooting/the-dreaded-404/

Cool it work. Flushing the WP rewrite rules and after that I logged off from my wp admin and still my forum page stay there with no 404 error.

Thanks Alot i keep reading the simple press wiki.

excellent. Thanks for updating us

You are welcome.

Three quick question.

1.      Is it possible to remove the simple press logo when a new user login for registration and add my own logo? I don't know is it good to ask this or not.

2.     My post don't showing social media icons on the post so i need help how to add them in the post and user login area?

3.   How to enable that Math option require to submit a post on my simple press forum?

Another question.

I make a regular user. As i login to the forum i receive following message;

Your Profile has been Updated

and i go back then i view the forum list, but still my new user unable to post?.

My next question

I make a category like:

                  Cars

Sub-Forum: Toyota

Sub-Forum: Honda

How i can remove Sub-Forum?

So that it just simply look like a sub forum.

Next Question.

My sub forums are showing in this position;

                  Cars

Sub-Forum: Toyota    Sub-Forum: Honda   Sub-Forum: Anything

Can I change them to look like this;

                  Cars

                        Toyota

                        Honda

                        Next Sub Category

Need your help!!!

is that group view?  no, its meant to just be a hint… on the parent forum page, they will show up at the top like you ask…

that will be possible with themes in v5.0…

no it's not a group view actually it's a parent forum on the top and then all other are like sub forums.

Like

                                Cars      (Parent Forum)

             Sub-Forum:  Honda   (Child Forum)

             Sub-Forum: Toyota    (Child Forum)

Any idea how can i do it?

currently, child forums are shown at the top… and then the topics for the current forum are listed…

so not sure what you mean… the only place forums are listed is the group view…

This will show more clear picture. My group name is on the top and then my forums and then my child forums and sub forums. If you need more explanation, so let me know.