Step 1: Create the library shown below.

Step 2: To find out where this library is stored (originally), and where to change the location (server location, or for vault) see below:

Step 3: To get this into vault, go to this location in and open the idw:

Step 4: Once open, you can confirm your library by using the model tree:

Step 5: at this point, its like any other inventor file. You can use the vault tab to check in the file.

Step 6: Now that it's in vault, others can do a "Get" of the folder. Then have them do Step 2.
Step 7: To use the sketch symbols, go to the annotate tab, click "Insert Sketch Symbol", and pick the symbol from the library.

I couldn't find this example of how to share a sketch symbol library. I hope this is helpful and saves research time.