Concentrated HCl is typically 12M (or 12N), and it is prepared by diluting it in 1 part to 5 parts water. (ie: 100ml to 500 ml). In other words, using the conservation of volume equation M1V1 = M2V2 , where M = concentration and V = volume.
You must determine the concentration first of the concentrated HCl, typically concentrated HCl is a 36-38% HCL which works out to about 12-12.2 N concentration. From there all you have to due is...
You must take 88,8 mL concentrated HCL and fill up to 1000 mL with distilated water. (REMEMBER: ALWAYS ADD ACID TO WATER! - add 88.8mL to 900mL water and dilute to final volume = 1L)
The simplest...