Please tell me how to make DLLs?

[jian2587]

I want to create some new functions and put it in a DLL
then declare it and use it.
But How?
I tried this...Man I am stupid
(I open a new DLL project)
sub abc
msgbox "abc123"
end sub
'module
public declare function abc()

'After compile to DLL i use it like this
public declare sub abc lib "c:\abc.dll" ()

Private Sub Command1_click()
abc
end sub
But it keep on display an error
Could anyone tell me how to make a DLL?