scr_fct_web = summary data
scr_fct_exact_access = detail data
scr_dim_XXXX = dimension tables of what the name suggests, for example, scr_dim_user has all the user names, and scr_dim_site has a list of all (web) site names.
the detail data has data dated by epoch time. For example, 8AM, March 2, 2012 CST is 1330675200 in epoch time.
the summary data has the date split into days since epoch and hour of day. For example, 8AM, March 2, 2012 is day 15401 since epoch.
Mapping the site to one of the two data tables is done through the scr_dim_site_request table. For example, to find summary records for www.mcafee.com on March 2, 2012.
scr_fct_web.site_request_id = scr_dim_site_request.site_request_id
AND scr_dim_site_request.site_id = scr_dim_site.site_id
AND scr_dim_site.site_name = 'www.mcafee.com'
AND scr_fct_web.days_since_epoch = 15401
Hopefully that helps.