So, I am coming from Yousician and have been playing about a month. I have the notes pretty good down in memory(A and D).
When trying to play Born in the USA or listening to the lessons. Do I play just the first beat of each chord or every beat. I.e: strum beat1 then beat2 then strum beat 3 and then beat 4 before moving on from lesson 1: changing from A to D ?
Welcome, Johan!
When you’re first starting out, playing the chord on the first beat of the bar is a good place to start as you’re learning how to strum and keep time in the context of a song. As you progress, you can move to other strumming patterns – for example, a downstrum on each beat, or a strumming pattern including upstrums (such as “Old Faithful,” which Justin teaches later on in Grade 1).
As for moving on from Module 1, there is a lesson at the end of the module suggesting criteria for moving on:
" 1. You’ve memorized the A and the D chords.
2. You can change between A and D at least 30 times a minute. If this seems impossible and you can’t achieve it after a few weeks, you can move. Later on our journey, you’ll learn some other tricks to switch faster between chords. I don’t want you to get bored! 
3. Nitsuj spent 4 practice sessions on Module 1 and took around 5 to 6 weeks to go through Grade 1. Check him out to help you decide when he felt ready to move on."