Hey Christos,

Those combinations are fine mate.

Keep things simple to start with - focus on technique rather than speed or power.

Once you have mastered the basic punches / transitions, you can add:

a) Head movement: i.e. Jab - slip right - right hand - roll.

b) Foot movement: i.e. Jab - right hand - step forward jab.

There are some very good demonstrations of all the basic skills (in isolation) you'll need to learn at the following link:

Edit - I'm not allowed to posts links till I have 5 posts. Search on youtube for "myboxingcoach".

Regarding how often to hit the bag:

Seen as you are you new to boxing, to start with, I would aim for 2-3 sessions per week on the bag and 2-3 sessions shadow boxing.

Hope this helps.