There various ways that this can be accomplished.
Here is an example based on the northwind database table employees
SELECT Employees.EmployeeID, Employees.LastName, Employees.FirstName, Employees.Title, Employees.TitleOfCourtesy, Employees.BirthDate, Employees.HireDate, Employees.Address, Employees.City, Employees.Region, Employees.PostalCode, Employees.Country, Employees.HomePhone, Employees.Extension, Employees.Photo, Employees.Notes, Employees.ReportsTo
WHERE (((Employees.LastName)=[Enter LastName]));
What this will do is ask for the parameter value to be enter for the field name 'lastname'
this is done by going to your query design selecting view sql, then write your sql statement here. (which is the example above) use your own database and table. Base your find button on the query you create.