Tummy time!

My son is 6 weeks old now and I'm just wondering how much tummy time he should be doing daily now! Also what else should I be doing with him every day? Other than cuddle and talk to him! I just wanna make sure he is stimulated enough and doesn't get super bored! He spends a lot of time in his swing because he's super gassy and has reflux and I just wanna make sure I'm not hurting his development at all!!! Any advice would be great!