You can setup your subdatasheets in the frontend by opening the table in
design view, rightclicking somewhere on the table and selecting "Properties"
... from there it's pretty self-explanatory ...

However, Tim's advice is still solid, and there are definite performance
issues associated with the use of subdatasheets in a split application.
Remember that there is NO error handling associated with directly table data
entry. You can achieve the same thing using the traditional form/subform
setup.

Anything you can do with a table datasheet you can do with a form, except
that with a form you have more control, you can help the user, you can
check for errors, you can hide or protect anything that needs it, you can
provide helpful defaults, and you can (cont page 94...)

Forms are not hard to design, and the wizards take away a lot of the work
for you. If you particularly like the grid layout, you can still create a
form that looks like it; and subforms are specifically designed to allow
drill-down type queries from the parent to child data.

You really are (a) doing your users a grave disservice in making them use
table sheets, and (b) putting the data themselves at risk too.

Best wishes

Tim F