If you are looking to invest in a company provided money purchase pension, then your company should have put you in touch with their financial advisor. This advisor is probably a tied advisor, but will probably know more about the options in the scheme than an independent financial advisor would.
If this is not an option then you will either need to either Be Your Own Financial Adviser or find another advisor.
Normally when looking for financial advice, you have the option of tied, or independent financial advisors. Tied advisors will try to sell you the products they promote and will usually take a commission on those sales. Independent Financial Advisors should know about a wider range of providers and offer you the option of paying them by either an up-front fee or taking a commission on products you buy. For a major investment, like a pension scheme you might be paying into for many years, the up-front fee approach is often the cheapest overall.
A good guide to finding an IFA can be found at Picking and paying for the right IFA!.