Something like the following will work. You will have to substitute the specific names, like "txtID", "recordid", "form2", for the real names.
This attempts to save the current record, then open the next form, then set the next form's ID to whatever you have currently open, then closes this form.
[tt]runcommand accmdSaveRecord
docmd.OpenForm "form2",DataMode:=acFormAdd
Forms!form2!RecordID = txtID.Value
DoCmd.Close acForm, Me.Name[/tt]
There are many problems with this entire idea. What happens if your user saves the first part properly, but doesn't finish saving the second form? How are you going to handle that? Are you going to let them come back later and re-enter the second part?
Also, what happens if they need to make edits? What happens if they need to delete a record?
There's too much room for user error with this sort of thing. I don't recommend the 'two-form' approach to enter a single body of data. And no, I don't know your specific situation enough to give better advice.
Pete