Tutorial how to make chain

1. Step 1

   firstly open a sketch to front plane and draw sketch like this
   
   

2. Step 2

   use trim command
   
   

3. Step 3

   use circular pattern command
   
   

4. Step 4

   connect the circles and use circular pattern command again
   
   

5. Step 5

   and extrude the sketch
   
   

6. Step 6

   open a sketch side of part and draw 2 circles
   
   

7. Step 7

   extrude it
   
   

8. Step 8

   go back side, open a sketch. close the back side with extrude
   
   

9. Step 9

   use fillet command
   
   

10. Step 10

    you can add a thing like this
    
    

11. Step 11

    all done:)) your chain is ready. very simple