Need assistance synchronize a fork with it's parent

I need assistance synchronize a fork with it's parent

    https://github.com/DG12/ruuvitag_fw
    This branch is 5 commits ahead, 29 commits behind ruuvi:master.

I want to revise main.c and the issue a pull request.

Sorry, but I am lost.

Seems that I am trying to do something simple.

Any help / comments would be appreciated.

SIncerely,

Dennis German