The new Bolshevik government were struggling to run the country as money was running low, people were starving, so they decided to back out of WW1, this made the other European countries see them as weak and not legit. In the conference after WW1 to decide what to do with Germany and the aftermath, Russia wasn't invited because they backed out of the war early.
Appointed positions are given to a person by another official, while elected positions are voted on by people living in the area. appointment makes it easier and quicker to find a person for a position. voting gives the people a say in what happens in their community.