You just need to have a Calling statemet after each menu item, like this.
Create Menu "Test" ID "12" As
"Preferences" Calling Prefs,
"Leads" Calling Leads,
"LeadsRemain" Calling LeadsRemain,
"Accts" Calling Accts,
"AcctsRemain Calling AcctsRemain "
Alter Menu Bar Add "Test"
And a Sub Routine hooked up to each of those, like this
Title "Hello again"
Repeat the above for the others.
The MapBasic help docs have some really good info on these, just look for 'Create Menu' and 'Dialog' and you should find the help docs. There are loads more options for the menu items and dialogs than I provided, for example you can add Help text, IDs so you can alter them as the result of other actions and more. Like I said, the MapBasic help docs are invaluable once you know what you're looking for.
Good luck, and if you have any further problems just let us know!