Serial one-to-many tables

I need help with design of a database I am writing to keep track of
procedures that I do on patients. For each patient, one or more procedures
can be done. For each procedure, one or more locations can be sampled (I want
to keep track of the sequence of locations sampled, i.e. 1, loc2R; 2, loc2L;
3, loc7; etc). For each location, one or more samples (pass1, pass2, pass3,
etc.) can be taken. For each sample there is a result (pos, neg,
non-diagnostic).

I've come up with this series of tables:

tblNames
NameID
LastName
FirstName

tblProcedure
ProcedureID
NameID
ProcedureDate
ProcedureType

tblLocation
LocationID
ProcedureID
LocationSequence
LocationName

tblResult
ResultID
LocationID
PassNumber
PassResult

I keep getting lost trying to create a form or sequence of forms that will
enable me to enter all the data. It seems that I need a subform
(Location:Result) inside a subform (ProceduLocation) inside another
subform (Name:Procedure). On the highest level form (Name) I want to be able
to select from the existing names (shown as LastName & ", " & FirstName) or
enter a new name. Any help with fixing my database design would be much
appreciated. Thanks.