1. filter for the activities that you want to add resources to 

then highlight them all and rigth click and select assign and assign a resource to them

next export the activities and resources and add any additional resources here

2. its your resource has ot be setup to auto compute actuals

go to your resource directory and for the resources that you are using lick on the details tab and make sure that Auto compute actuls is checked.

next go toyour Projects directory make sure that your project is open and highlighted

next to to the clculations tab and make sure that under Resource assignments that When updating actual units or cost that the Subtract actuals from actual at completion  is checked.

also make sure that Recalculate Actual units and cost when duration % complete changes

3. if you plan to add the SAME RESOURCE to an activity MORE than ONCE in the Projects directory go to the Resources tab and under Resource Assignments make sure that Resources can be assigned to the same avtibity more than once is checked.

4. if your are using physcial % complete to progress your schedule you MUST run a global change so that the Duration % complete eqauls the physcial % complete becasue ATUO computing ACTULAS is derived form DURATION % COMPLETE as stated above.

5. To add a global change go to

tools

global change

add

where physcial % complete is grether than 0 

then duration % complete = Physcial % complete

then on the right select change

then on the bottom select Commit Changes

DONE