1. positively connect with someone
get along with friends/colleagues
When you 'get along with someone' it means you have a good personal connection and relationship with them and you enjoy each others company. This is a casual phrase that can be used to talk about personal and professional relationships.
2. the process of performing/completing something
get along with work/project/assignment
How you are 'getting along' with something you are doing refers tot he progress you have made or are making. You can ask someone how they are 'getting on' with a project or a person. "How are you getting on?" is a good question to use if you want to casually check on someone. If you are 'getting on with it' you might not be enjoying the process but you are making progress. "How are you getting on with the end of year accounts?" - "I'm getting on fine, it's tedious, but I'm getting on with it!"