tina

Yes you use the total in the fixed asset account for the value to clear that account. ie if a building fixed asset account has the value of 150,000 the journal entry would be

debit gain loss 150K
credit fixed asset building 150K

Yes each fixed asset account that was sold, and each associated accumulated depreciation account too

In the deposit, leave received from blank, and just select the source (from) account.  Using received from would create a credit entry which you do not want to happen