Creating A Subform

hi guys this is my problem : might be a bit long but here it goes!
tbl 1:
ServiceRecord_ID
veh_no
date in
date out
status

tbl2:
Employee_id
ServiceRecord_ID
task date
action taken
spare parts required
Part_Id

tbl3:
PO_no
part_ID
price
quantity


now i want to create a form to input the datas into tbl one

the layout of the form looks like this

ServiceRecord_ID
vehicle no
date in date out
status

subform:
task history

employee_id task date parts action taken parts required

in the subform , the end user can just input the task history into the subform.

So what are teh steps that i must take>?