That question is almost in the same family as "How to program a PLC".
You have the software and the manual?
Generally:
- Parts is predefined object with functions, like switches, lamps, graph, keypad, different type of displays etc etc
- Tags is functions without predefined drawings/object. Pop Up Window, Rail, graph, touch button ++ many types of animation.
- Script is ... script. If then else. Most logic, but there are drawing commands also.
Read The Fine Manual!
Regards