Its pretty much the same as paper based application, once you gather all the documents accordingly(i got everything attested by notary lawyer) all you gotta do to do is combine them into 4-5 single pdf files and upload accordingly to the gc portal.
There are various online website such as ilovepdf, smallpdf where you can merge multiple pdf files, compress them, edit and pretty much everything like converting to a different format. I used https://www.ilovepdf.com/
Visitors visa is one among the TRV, while applying for student permit if you have filled up the form (IMM5257B) -(optional) you will get OPR otherwise you won’t.
Once you have your student permit approval, a valid visa and approved DLI, you can travel anytime with the required documents as stated in ircc website.
They might still be going through your eligibility and it might take more time than the usual processing period provided by ircc. @Bishops2020 had a similar case like yours and received approval few days back.
Since it says Current activity/Occupation maybe you can put in Student and on the employer name/facilty you can use your last attended educational institute name.