Open the file
Select Manage | Security
From there you can create a new account and then either select and existing privilege set or create a new one. You then have the option to edit the privilege set.
This is also the same method you would use for any FileMaker database file you might choose to work with. The main proviso is that you have it open with a full access password before you select Manage | Security. (Starter solutions are not password protected when first created so you just have to open them to gain access to manage | security.)
PS. when working with Manage | Security for the first time, it's not a bad idea to first save a back up copy of your file. Then, if you accidentally lock yourself out of the file, you can toss that copy of the file and switch to your back up.
Thank you fort he answer; indeed you can create new privilege sets at will as you describe. Unfortunately however you are stuck with the ones that came with the started solution and you can't erase them or edit them because they are "grayed out". That being the case they are still operational and lock out any editing of the objects that you might want to modify. If anybody has any idea how to get around this it would be appreciated.
The only "privilege sets" that come with the starter solution are enclosed in brackets  such as [Full Access] These are "hardwired" privilege set options that come with any fileMaker file. If you create a brand new file, you'll find the same 3 to start with.
But you do not need to set up any accounts to use them if you don't need to and can add as many new ones as you'd like.
Hi and thanks again; my point is I want to get rid of them, the hard wired ones that is, the reason being that if i were to import a new table from Excel lets say, then these hard wired ones prevent me from defining the fields in the imported table, or even use the fields in the first row of the Exel table as headers, which is a shame. I am going to assume that hard wired means there is no way I can delete them or modify them . It would seem that the inability to do so detracts from having the Starter templates usefulness as exemplars.In any event the FileMaker Pro developers must have a good reason for all this wiring. Bye the way I am aware that I can feed data from an Excel table into any predefined hard wired field which is nice but limits what otherwise could be done. Thanks again for your input
a) you can't get rid of them.and to repeat, these are standard settings found in every FileMaker file.
b) they do not prevent you from doing anything with your file. When you first open a starter solution and so long as you do not change setting in Manage | security, the file is fully accessible to you to make any needed design change to the file. You actually have the file open with the [full access] privilege set specified if you have not changed any settings.
All you need do is Select Manage | Database from the file menu to open a dialog where you can define fields, add new tables, define new relationships and so forth.
I sugest that you describe how you are going about "adding new fields" and then I can help you get around whatever hurdle is preventing you . (It's not the privilege sets, they don't have anything to do with your problem.)
More specifically I am using the Content Management Starter(CMS) into which I am putting photographs. I have an Excel sheet which contains many more columns with headings that are not defined in CMS. I was able to import the Excel file as a new table in CMS. The import operation assigns the the columns to filed names f1,f2,f3, 3tc. I then am unable to change f1, f2 etc because they are locked by the hard wired [..] privilege set I think. Then what I wanted to do is create a relationship between the imported converted Excel file and the native CMS table in order to define a second layout with fields from both tables. Anyway that was the plan and the thought is that perhaps this would not be possible if I cannot do a simple operation like renaming a field.
You say I can define a table and fields and these will not be locked and then feed the data into them from the Excel source I'll try that. Thanks again
I then am unable to change f1, f2 etc because they are locked by the hard wired [..] privilege set I think.
The privilege sets have nothing to do with this. You have the table open with the account name of Admin and the privilege set of [full access]. This gives you complete freedom to make any design change possible to your file.
Open manage | database | Fields
Select the new table created by your import from the table drop down.
Click field f1 to select it.
Change the name in the field name box at the bottom of this window and click change.
You have now changed the name of this field.
Then what I wanted to do is create a relationship between the imported converted Excel file and the native CMS table in order to define a second layout with fields from both tables
From Manage | Database | Fields, click the relationships tab and you'll see the existing table occurrences in this starter solution plus one for your newly created table. You can make more table occurrences and drag from one field in one table occurrence to a field in another table occurrence in order to link them in a relationships.
But you may want to consider using Manage | Database | Fields to add more fields to an existing table instead of using the "new table" option and then importing again so as to import the data directly into one table instead of having two related tables.