when you apply you need to have cover letter explaining you situation that you are on closed work permit at XXX company doing XXX job with dates and all and also mention that you are adding below
1. Reference letter(this should include job duties as well, so that immigration office can determine NOC code),
2. Pay slips of last three months.
3. Bank statements(these should determine that you have funds to support your family).
4. copy of your existing work permit
5. copy of your passport
6. Marrigae certifcates.
7. birth certificate of your children.
8. experince letter of your wife
9. education documets of your wife.
Any relevant documents you have, attach these with cover letter, this will be one big PDF.