I’m just gonna move it here so you have to get into the thread and @Jazzbass19 doesn’t have to worry about us filling up the welcome thread 
It’s all a balance thing. There’s no time someone else can tell you. But practicing for a long time puts more strain on your hand, tendons and everything and I don’t know how far you got into techniques. For me it was impossible to play the octaves with my pinky for longer than 5 minutes at first. Now I can do half an hour of that.
So practice as long as you feel comfortable with. A little bit uncomfort might be okay for new things but never pain.
2) when do I practice, after each lesson or each module?
Probably after each lesson. You can either replay the workouts as often as you want to until you are satisfied and can play it in a relaxed state or have a look here: BassBuzz YouTube Video Guide
It connects the B2B course to the Bassbuzz youtube videos. So when you learn something in the course you can go to youtube for additonal training resources for a lot of lessons.
It is also fun to use the playalongs in the course extras. Joshs explanations are welcome but I don’t need a chord progression explained the Xth time.
That said if you feel comfortable playing the workouts to the lessons and are nailing it - move on in the course! You can decide on your practice routine after you finished the course. You will probably also have more of an idea what things you want to learn and what things you are struggling with.
Since I started talking about practice I can’t hold back: In order to play fast you have to learn to play slow and get faster. It can’t be said often enough. Nothing is gained if you tigthen up and fumble the coordination. Rather go slow and right than fast and messy.
Also it’s sometimes worth it to move on with the course instead of fixating on nailing the fast workout. Especially Module 4 Lesson 6 - most, maybe all people can’t do that on fast after going through the whole course. All of us are working on it though.