I have always used my BB for personal email, but now I need to use it for company email. Do I need to be BES for this? If so, how do I switch to BES: through phone provider or through basic bb settings?

can you help me to get my personal emails sorted am having trouble

You have to be on a BES data plan, not just BIS data plan. Then your company needs to have a BES. Check with them for activation.