Help with selling portion of condo.
Hello, I am hoping someone can help me out with a question or two 
I currently own a condo (CONDO 1) (I owe 350,000 on the mortgage, value of unit is 700,000). It is my primary residence. I have bought a pre-construction condo (CONDO 2) and should move into it later in the year. I want to keep CONDO 1 as a rental unit. However, I want to sell 50 percent of CONDO 1 to my brother and we will keep it as a rental property. I am completely new to owning rental properties. I am wondering what the best way to do this would be. (Yes I will be seeing a professional for advice but I would like to give it some thought and research it a bit on my own first so I am prepared in advance).
My brother has 100,000 on hand and would need a mortgage for the remaining 250,000. I am curious how it works with a partner. Do we both need to be on the mortgage? I assume it would be simple if he had all 350,000 in cash as he could just give it to me and I could add him to the title..but he does not.. Can anyone offer any suggestions to point me in the right direction?
Thanks so much!

I currently own a condo (CONDO 1) (I owe 350,000 on the mortgage, value of unit is 700,000). It is my primary residence. I have bought a pre-construction condo (CONDO 2) and should move into it later in the year. I want to keep CONDO 1 as a rental unit. However, I want to sell 50 percent of CONDO 1 to my brother and we will keep it as a rental property. I am completely new to owning rental properties. I am wondering what the best way to do this would be. (Yes I will be seeing a professional for advice but I would like to give it some thought and research it a bit on my own first so I am prepared in advance).
My brother has 100,000 on hand and would need a mortgage for the remaining 250,000. I am curious how it works with a partner. Do we both need to be on the mortgage? I assume it would be simple if he had all 350,000 in cash as he could just give it to me and I could add him to the title..but he does not.. Can anyone offer any suggestions to point me in the right direction?
Thanks so much!