Edit a screen cast video

Hi, I have to make a screen cast video - I have 3 videos (2-3 mins each) demonstrating tasks done on the screen. We need to do the following tasks to the video : 1. Remove pauses within the 3 videos 2. Add text which describes the action 3. Remove out un-necessary sequences 4. Create shareable small sized video I want to provide someone with experience in creating screen cast videos. Would like to see prior experience.