How can I assign different characters to different keyboard shortcuts on Mac?
If the manual provided with Ukelele is not sufficient, you can ask for help with specific problems at the users group

https://groups.google.com/forum/?fromgroups#!forum/ukelele-users

It might be easier to just use the US Extended layout.  Shortcuts for Turkish special characters are

option c, then c  ç
option b, then g  ğ
option w, then i  ı
option u, then o  ö
option c, then s  ş
option u, then u  ü  

PS Have you tried the Turkish Qwerty layout (instead of Turkish Qwerty PC) in system prefs/language &amp; text/input sources?  It may also do what you need via the option keys while keeping the usual other shortcuts.