The keyboards for Hebrew and Greek + Transliteration may not be ideal
for you.
These instructions will show you how to make and save changes to
them.
Most of this page is devoted to the PC, but the principles also apply
to the Mac.
Mac Layout Editing
Download Ukelele, which was developed at SIL for the many
languages they support.

The following instructions for the PC software
follows similar principles.
PC Layout Editing
As an example, the following is a change shows how a change was made
to the first version
which missed out the
Greek comma in favour of a mid-sentence raised-period.
Users requested that the comma should be left as a Greek comma,
and the
raised-period should be somewhere else.
Although the raised-period is sometimes known as the Greek
semi-colon,
we need to leave
the semi-colon alone because it is used in Greek as a question mark.
So instead the raised-period was mapped to the key for the colon.
However, the colon is useful for writing verse references, so it was
left within easy reach,
on the
Transliteration keyboard. If you disagree with this, you can change
it.
To make changes to the keyboard, download
MSKLC.exe
(Microsoft Keyboard Layout Creator – get the latest version from here)
Download and run the latest version of MSKLC.

(When you run it, you may be prompted to install .NET if this isn't
on your computer.
A link to install this is on the same page.)
Click on “Setup” then “Next”, “I agree” etc. till it is installed.
Now find the keyboard files (those ending in “.klc”) in the folder "Editing PC Keyboards"

Double-click on the “GreekTH” keyboard to
open it in the Keyboard Creator.

To make the change proposed above (ie move the Greek raised-period from the comma key to the colon
key):

This makes it easy to type a raised-period as well as a comma in
Greek.
But a colon is useful when writing references, e.g. “Matt.
1:1”
To write this in the Greek keyboard, you would normally turn on Caps
Lock,
which turns the
keyboard into English & Transliteration.
Therefore the colon could usefully be added to this transliteration
keyboard.
To do this, click again on the semi-colon key (ie the raised-period key) and click on “All…” then tick
“Advanced View”

Type the codes for semi-colon and colon (U+003b & U+003a) in the
bottom two boxes and click “OK”.
You can test these changes by ticking “Show the Caps Lock”.
Or you can test typing with it by clicking on “Project” then “Test
Keyboard Layout”
To save these changes, click on “File”, “Save Source File
as…”

Save it in the same place as the original keyboard layout (ie in Program Files:
Tyndale Unicode Font Kit: Editing PC Keyboards) with a slightly
different name (eg GreekTH2.klc)
so that you can
reverse the changes if anything has gone wrong.
To install these changes as your Greek keyboard, you must first
change the properties then build it.
To change the properties, click on “Project” then
“Properties”.

You should change:
Click “OK” to save these changes.
To build the project, click on “Project” then “Save DLL”

The warning that “Verification failed” is inevitable in any academic
Greek or Hebrew keyboard
because you will be
warned that they use characters not available in normal fonts.
Click on “No”
(or “Yes”, if you are curious). Then wait while
it builds the files.

Click on “Yes” to open the folder with the new keyboard and
installer.

To install this new keyboard on your computer, double-click on
“Setup”
After a long time with nothing visible happening, it finishes with:

Click on
“Close”.
Now you have to make this keyboard your default Greek keyboard by
turning off the one you have already installed.
To do this:

Highlight the original keyboard and click on “Remove” then on
“OK”
To check this has all worked: