Or, if you have been particularly adventuresome, perhaps you purchased your BJD as a kit. (Think Volks or U-noa.) I recently purchased a U-noa Qu'luts Sist from Japan via Crescent Shop. Unless you buy your U-noa from someone who has already assembled it, this is how your doll will arrive:
This scene of dolly carnage would have terrified me when I first started collecting BJDs. Assemble a doll? Me? Are you kidding? The instructions are in Japanese!!! Yes, they are, but they are fully illustrated with line drawings that make it perfectly clear what to do and in what order to do it. Everything you need is in the box. Well, nearly everything. The only tool provided is a length of wire. You will need a dab of epoxy cement, as well as a craft knife. I also find it helpful to have a hemostat (available online from web sites that cater to doll crafters) to act as a third hand.
The first thing to do is to open the cellophane bags and make sure you have all your parts. There is an extra part that looks like a lower leg, minus the hole for the string to pass through. A small piece of paper explains, in English, that this is a test piece for trying out your colors before you paint your doll. It's a nice touch. I purchased an optional large bust torso for my doll; the default for Sist is the small bust. There is also an extra faceplate: a sleep face that Crescent Shop included as part of a promotion.
I like to lay out my pieces in order as I will string them, being careful not to mix parts labeled L and R. (Apparently I was not careful enough, because I did indeed mix some left and right parts -- and then wondered why the doll's elbow joint was facing front instead of back.)
Next, glue the two ball joints to the upper thighs. Try the pieces for fit before you apply the epoxy. You may find, as I did, that there are extra bits of resin adhering from the mold. These need to be shaved off with the craft knife. You might also want to remove the seam lines, also left over from the molding process. I left them alone, but I could have sanded them with an extra fine sanding sponge. Wear a face mask if you do this, because resin dust is toxic and you don't want to breathe it in.
There are two lengths of elastic cord in the kit. The shorter length is for the arms, the longer one goes through the legs, torso, and head. Knot the shorter elastic as shown in the diagram, hook the wire onto it, and string the wire through the torso and out one of the armholes.
I like to hook the free end of elastic over the neck while I string the first arm. That way it won't work its way back inside as I am stringing. Alternatively, I could clamp it with the hemostat to keep it in place.
After you have attached both arms, knot the longer elastic cord, fold it into two equal lengths, hook the wire tool onto it and pull it up through the torso and out the neck. Make sure the knot is off center. You want it to stay inside the torso, not pull up into the head.
The kit contains three short wire pins. Two are part of the eye mechanism. (I don't use this.) The shortest pin holds the longer piece of elastic inside the head. It looks so fragile you imagine it couldn't possibly work, but it does. Pass the pin through the loop in the elastic and place it securely in the space hollowed out for it.
Now you can thread the elastic through the legs. The feet take a bit more effort. What you have inside the foot is a tiny S-hook attached to a tiny pin embedded in the resin. The S-hook wiggles freely; making it grab the elastic can be a challenge. I don't know why I attempted this by hand. I should have looped the wire tool around the S-hook and guided it over the elastic. Something to remember next time. Once the feet are on, there is only one piece left to put in place.
I don't know if there is a technical term for this part, but it corresponds to the small of the back. It serves to keep the elastic cords in their proper channels. Without it, your doll will jacknife in the middle, unable to stand or sit straight. You insert it from the rear into the space between the upper and lower torso. The hook goes uppermost, between the elastic cords, and the part rests securely inside the lower torso.
Properly strung, your doll can stand on her own without a stand or other prop. Sitting, U-noas get a little help holding their position from a small protrusion at the top of each thigh joint. (I hope you didn't carve these away!) These bumps disappear into the buttocks when the doll is standing.
If you are restringing a doll from another doll maker, make careful note of how it is strung before you take it apart. Not all doll makers bury the knots inside the torso; in some dolls the knot is inside the head. You may find an S-hook inside the head instead of a straight pin. My vinyl Innuendo's cord passes through a hard plastic washer and a wooden ball (something I haven't seen in any other doll) before being knotted inside her head. Draw yourself a blueprint if necessary. You want to be able to put the doll back together as it was.
Some doll owners like to body-blush their dolls. The time to do this is before assembly, when it is easier to get at body parts from every angle. My personal preference is to leave the body the color of the resin. I will probably give my girl a French manicure. I have already given her a faceup, but that is a topic for another post. I hope you will come back to see how I paint her face.