My husband asked me to manage his 401k Defined Benefits Profit sharing
plan. He was just given a contribution from his company.  I know this
type has to go through a third party administrator, and in our case it
is a company called R-TECH. But do I have to go through a financial
advisor to buy investment stocks or can I buy them independantly and
then advise Third party administrator of stock purchase going into
401k?

Not to be nit-picky, but isn't a 401K plan a "defined contribution"
plan, not a "defined benefits" plan?

J.