Worked for my own company for part of the year- various filing questions

Hey Guys, 

First some background- I worked for an employer for part of the year (and worked for them from home) and was self employed, operating from my home the rest of the year.

  • In the small business income section:
    • Below the box for sales, why does it ask for self employment income reported on T4 slips (Box 81, 82, or 83)? Based on what those boxes are for, it seems like they only apply for specific types of businesses? (i.e. barbers, uber drivers)
      • Note that I run a consulting small business (of just myself) and pay myself the company's earnings from clients (note that the company consists of just me so client earnings is effectively my salary)
    • I earned less than $30k in gross revenue in my first year of business. Therefore what, if anything, do I put in the following 3 fields:
      • GST, HST and PST (if included in sales above) If you included the amount of GST/HST, or PST, returns, allowances, discounts, and GST/HST adjustments and any WIP at the end of the year you elected to exclude in the amount entered above, enter the sales taxes received separately here. Learn More
      • For those using the Quick Method; GST/HST collected or collectible on sales, commissions, and professional fees eligible for the Quick Method
      • For each applicable remittance rate, subtract sales, commissions, and professional fees eligible for the Quick Method plus GST/HST collected or collectible multiplied by Quick Method remittance rate
  • In the self employment section, I saw the place to enter $$ spent on rent, electricity, etc but where would I input that for when I was employed, so that I can claim my work from home expenses from that time?

Thanks!