ok friend look what you have to do is:
For example if you have a table called data and in that table have a field called model then all you have to do is create a table relationship with the same data table called this is that when your relationships that you send the model field equal records same field model once done then you go and create a new field in the table called summary data set him and tell him CALCULATION type the following code:
count (data2 :: model) options that you shall not store data update cuandosea necessary.
I hope to serve you and understand if I am at your command.
There are three ways to count a group of records: the Count function and a summary field set up to count a never empty field in the table in which it is defined. If you have FileMaker 12, you can also use ExecuteSQL to count records in a table.
In your case, if your layout is based on your table of assets, you can set up a relationship linking assets to an added occurrence of Assets linking by the model number. Then, either the count function, defined in a field in Assets to count records from the linked occurrence of assets or a "count" type summary field from the linked occurrence of assets can be placed on your layout to show the total assets with that same asset number.
Ahh.. .thank you Web Cyed! Worked like a charm! Changes dynamically as well.