Son_of_a_tax

I have read hundreds of online topics about filling out the T2125 form, but I cannot find any clear information on where I deduct the wood, nails, cement, paint, tape, screws etc. (basically everything I buy to do a job). What section does it go into ?

Filled out the forms using auto-fill, when I got to the Review section, it put a HUGE amount in line 13000 Other income. I do not know what this amount is and I can't find it in the interview or anywhere in Netfile. How do I remove this amount. (FYI I was unemployed last year and it put $100,000 !! Wow I wish I had that!)

This year I will be doing my mother's tax return. She is not my dependant and does not live with me. Can I use my UFile account to do my return and hers (If yes, how do I add a profile?) or do I need to create a new account for her (separate from mine, with her own login, etc.) ?