Adding a discussion board/ blog

I am thinking about adding a discussion boar or blog (or both) to my pages (2 sites)
here is my question:
i will use one of my sebsites for example
my websites is https://www.classydesires.com
SHOULD i make a subdomain to link the board or blog to:
i.e: https://www.classydesires.com/blog
https://www.classydesires.com/discussion

is this the easiest way to do this with no interfearance on my page other than adding a link to it?

Also, my customers have obviously an account log in to shop.. can they use the same login s for the boards or must they use new ones?

any reccommendations on how do do all this the EASIEST way possible? (as I am completely retarded with coding and all the installs etc lol)

THANKS!!!!!!!!!!!!

SHOULD i make a subdomain to link the board or blog to:
i.e: https://www.classydesires.com/blog
https://www.classydesires.com/discussion
Added folders would be
https://www.classydesires.com/blog
https://www.classydesires.com/discussion

SubDomains would be
https://www.blog.classydesires.com
https://www.discussion.classydesires.com

is this the easiest way to do this with no interfearance on my page other than adding a link to it?
Either way is acceptable and little difference
Also, my customers have obviously an account log in to shop.. can they use the same login s for the boards or must they use new ones?
The only "bridge" to allow this is for the forum script version phpbb2

kobra:

The only "bridge" to allow this is for the forum script version phpbb2

Sorry.. what is that?
i downloaded SMF as my discussion board and Wordpress as my blog

i downloaded SMF as my discussion board and Wordpress as my blog
There is no published bridge for either of those

A bridge is code that sync's the user details for account login