Here we go! You need to find the nearest Latter Day Saints Library, to do this go the the Family Search Web site and follow the prompts. If you have already found the person(s) you are looking for bring up their IGI record on Family Search, scroll down to the bottom of the record form where it says Source Call Number click on that and it will tell you which source the information came from. You can order the appropriate films through the LDS Library for a modest cost. But you can pinpoint the film(s) you need, that is you don't have to order the whole lot of films listed for example...
Say you are looking as I am for signs of the TOURNER family at St Bride Fleet Street between 1814 and 1835., I know that my gg grandmother and her sister were married from St Bride in 1830 and 1837 respectively.
I went to the Family Search site, clicked on Library and then followed the instructions. I got a list of all the records LDS have in regard to St Bride and was able to choose the films I needed. From my gg grandmother's sister's marriage record I obtained her address, her husband's address, his occupation, the names of the witnesses and names and occupations of the fathers of the bride and groom.
I hope this helps and that you have an LDS Library close handy. Cheers