The work you'll be doing is designed to give you a strong aerobic base and will allow you to go farther, more often and with less effort. We'll use the Rate of Perceived Exertion scale–or RPE–for all of these activities. The RPE scale is a number from 1 to 10 that corresponds with how hard you are working. You should try to use a light but comfortable amount of effort which is noticeable but you should still be able to maintain a conversation–a 2 to 3 on the RPE scale. Follow this link to learn more about the RPE scale. Rate of Perceived Exertion
As you progress you'll feel better, recover with less rest, and each effort will feel easier as time goes on.
The aerobic base you'll build will be very useful when you decide what you want to take on next, whether it's starting a hill climb program or challenging yourself with long distance runs such as marathons or ultras. Don't worry though if that's not your thing, you can still keep running with friends but you'll be able to talk more easily and focus less on the effort.