Generally, you are allowed to pre-select. For those courses that do not conflict with your required courses, it is best to choose more in the pre-selection.

In about five days, you will know whether you have been selected as a pre-selected subject. This is called direct election.

If the subjects you choose are enough for your credits, you'd better go directly to class to complete the credits.

If you find that you didn't take any pre-selected subjects when choosing, then you must choose again. If it really doesn't work, you can choose again next semester. Anyway, just finish the credits before junior year.

Generally speaking, if you are pre-selected, you may not be selected. If you are selected, you can go to class. If you pass, you will get credit.

There is no chance to choose first. Some popular elective courses ensure that the list of candidates is random.

It's a mess I wonder if I can help you.