To care for your corset:
Hand wash with mild soap in very cold water. Blot dry by rolling in a towel and squeezing out as much water as possible. Hang in a well-ventilated area (i.e.: in front of a fan) to dry. Do not dry-clean. Store loosely rolled or gently folded in an area large enough to accommodate corset without bending. Do not store corset after washing until thoroughly dry.
Lacing your corset:
Your corset comes with two laces. Tighten these laces to adjust the fit. Some ladies in period preferred to use three laces for greater control of the fit. To add a third lace, remove the top lace from two sets of eyelets and the bottom lace from one set of eyelets. Lace the new lace through the three open sets of eyelets. Your laces will stretch with wear and will need to be adjusted from time to time. When this happens, just tighten the laces back to the fit you want. Corsets with busk or hook and eye closures do not need to be laced and un-laced completely every time they are worn.
Earlier period corsets (such as Elizabethan) come laced in the period manner. It is, of course, necessary to undo them in order to put them on. It is quite possible to lace them in the 19th century manner, which is very similar to the way we lace modern shoes, but the correct historical method is diagrammed here for those who prefer authenticity.
Wearing your corset:
It is extremely important to remember that wearing a corset can be very tiring. I do not suggest donning a corset for the first time with the intent of wearing it all day. If there is an occasion looming on the horizon for which you will wish to wear your corset all day, it would be wise to "train" yourself to wear it by starting with a short period of time and adding to the length of wear until you are comfortable in your corset for a full day. There should be a gap of no more than two inches between the back edges of your corset.
Because of the many adverse health effects, I strongly recommend against the use of corsets for body modification. However, if you must attempt tight lacing, please consult the available literature on doing so in comparative safety.