Shall i cut the bottom leaves and stem?

There's this pruning method called lollipopping that works wonders with cannabis plants! You take off any growth that doesn't get good light. Shade leaves and even some small off-shoot branches might need to be removed. But, don't worry. It will help your plant grow faster and develop new bud nodes in better places. Also, another good practice to get in the habit of, in my opinion, is removing shade leaves that cover bud sites. This will also encourage growth in the right places.