Not comlpetely sure if this is what you’re after, so please forgive me if I’m telling you something you already know....

To resource (and by extension cost) load your plan;

Click Data>Resources... you will get a dialog which gives you the resource library for your project plan. Here you can enter all your disciplines and costcodes. You can also fix cost per time period to your resources and assign specific availability calenders to them.

On each activity you can place the resources. Where you have several subcontractors, you can use cost codes to designate which subcontractor provides which trade activity by activity. If you choose to use cost codes more formally (for contract works, Extra works etc), then you may need to specify the supplying company directly on the resource code, so you have F1 and F2 to designate Fitters from Subcon 1 from fitters from subcon 2, etc.

For more complex plans, you may wish to import the data directly as manual entry is somewhat onerous. For this you can use the .DBF import or Pervasive ODBC or Batch file systems, amongst others. These are a bit complex and tough to explain in a forum post though. The DBF method is probably the easiest to use, click tools>project utilities>import once you have created the data in the correct format in a DBF file (use Excel or Access then export to DBF). To get the correct format, export some sample data first through click tools>project utilities>export so you get the column headers right.

Remeber backups are your friend, it’s very easy to make a big mess with import / export.