The use 'being' and 'be'

Hi, i cant seem to understand the usage between 'being' and 'be'. For example: As a child i was always 'being' the naughtiest one at school, or, As a child i was always 'be' the.......?
Another question, i read this adv few days ago, it said "It is a great pleasure to introduce our company being membership agent since for years and focused entirely on buy/sell/rent/ investment of golf club...... blah blah blah.....the sentence sounds strange to me yet i cant figure out where the mistakes are, or it is perfectly well written? How about this, "It is a great pleasure to introduce our company being a membership for years and has been focusing entirely on buying, selling and renting investment of golf club?
Anyone please tell me? Thanks