YOu can use google to look up the Alt + codes which you can use on your keypad to the right on most or all keyboards.
If you have trouble with getting them to work right in some spaces, it may be that the keyboard is defective, or maybe the program for that in your own computer doesn't mesh well with the medium on which you are writing. Now I've reached the limits of my knowledge on this question. Good luck!
You can also program in other ways, but I don't know them.
Some keyboards have them already. Ask at your computer stores or departments.
You can also, in windows do Start / All Programs / Accessories / System Tools / Character Map which shows you all the characters with their numbers or you can just select and copy to the clip board. You make a short cut to the program by right clicking on the Character Map choice and drag the shortcut to the desktop