This should get you started:

1)Invoke the first script.
2)Check for the process id (If the first script is running).
ps -ef | grep "Process id"
3)If you get an output, sleep for "x" seconds.
4)If there is no output, the script has finished.
5)Still as a verifying criteria , you can create a empty file at the end of the script.
6)Check if the file has been created.
7)If the file has been created, start the second script.
8)Delte the empty file in the second script, which was created in the first script.

If you need more help, paste your code by trying above and we can help you.

Thanks!
nua7