2.) I will receive automatically the full BC amount and as soon as it is written to blockchain it appears automatically in my "Addresses" Tab as yellow line
If you've given a green address for deposit, then it'll be in the green ones.
over there in "Pay to" entry field together with a description and the amount and click button "Pay"
You don't have to enter a description if you don't want to. The description is just an optional field that remains to your wallet; it's not a message that is sent to the receiver.
Do I have any control from which of my yellow, non-empty addresses the send BC amount is taken?
Each time you have new change, they will be sent to an unused change (yellow) address. Doesn't that assist you?
How do I specify how much I am willing to pay to the miner as transaction fee?
Once you click “Pay” there's an “Advanced” button. Click it and you'll be able to set any target fee greater than 1 sat/vbyte.