Never had a mortgage.... but about to get one, question

Hi there

As the title suggests, I have never had a mortgage before, but some of you may have seen from other posts that I am about to help my sister out in buying her next property, following on from her divorce.

I have been talking to a great independent advisor and I know that we can get a loan/mortgage for the amount that we need (joint mortgage, sole tenant) plus a little bit more for a new kitchen for me, and I believe that this is very common. But my question is, how does this work?

When my sister (and bil) sell their home, they will take 50% each of the "profit" - does this money literally get paid into their bank account(s)?

Once my sis has her pot of money and we have found a property for her and we have the laon approved, what happens next - does the money get paid to me/my sis and we then pay for the property and the remainig money I can use for my kitchen? Do I need to state that to the lender? Or, does the money get paid direct to the seller of the property that we are buying?

It's just that I am borrowing money (with my sis) to buy her property and then using some of that money to upgrade part of my property - would that be a problem?

I feel a bit silly not knowing how any of this works at my age, but hey ho, willing to learn if anyone can help teach me.

I don't even know the ins and outs of buying a property and the various stages that need to happen, so you probably can't give me too much information!

Thanks in advance