The image shows an opened bottom half of a sphere which has a narrower groove than the top half. Attach 4 nuts loosely to 4 bolts & place the nut ends into the groove at the small cuts which are all 90 degrees apart.
Gently finger tighten the nut-bolts & then press the 2 halves together. The top half has a guide pin which you can use to line up with an indent on the bottom half.
Click on the Details Tab below for assembly instructions.