Use Blender to Create a Sims 4 Pose - For Absolute Beginners

You won't be loading the obj file into the game. You will need a pkg file(with a texture and the mesh that is same as obj file) if the item isn't already in the game.

The OBJ mesh is just going to be there in Blender to give you some help with the placement and pose adjustment, because it's really hard to get the height and placement right if you're for instance posing a sim in a chair or on a bed without a bed or chair to pose them with.

If you import in the object and let it be in the the original position, and pose the sim wherever you want them to be on/in/around that object, it's going to be a bit easier to place the teleporter in the middle of that object and have the sim placed where you want them to be (at least it is for one-tile items, multi-tile items can be a bit trickier to get right). 

Ingame, the items you've used in Blender won't follow the pose, so you'll have to use the regular objects from the buy/build menu (or accessories in CAS if you intend to do posing with accessories at some point).

When I open the blender, the rig won't show up. I tried 2.7 and 2.76 versions of the blender but still doesn't work. please help!!!

I followed the same steps, it still doesnt work :(

You need to link S4S to your game. Check "Settings" at the top and see if all the paths are properly set up to the Sims 4 path, Sims 4 in Documents, and Blender. You may also need to make sure you install the Blender plugins (they're in one of the S4S folders when you download S4S). 

How does your pose look like now?

Most of the time it just comes down to rotating the hand the way you want it. How you can rotate a joint depends on whether you click R once or twice, and on the view you're in. The Numpad 5 will change to orthographic view (usually simplest for posing), while 1, 3 and 7 toggle between front, right, and top view. 

If you need more control over a joint, hold in Shift while rotating, and the rotating will slow down. 

Sometimes you'll have to rotate the elbow and shoulder joints for the wrist to look good. It's a bit counter-intuitive in Blender, but it does makes sense if you think about how you move your own arm.

If you move the shoulder joint so the elbow joint is roughly in the area where you want it before you move the elbow (I tend to first put a slight angle on the elbow in Right View so I know where the bend is), then move the elbow and finally the wrist, it's much easier to get it right.