starting £50 k investing

Hi all
Applied last week 50k rouite
Need some expert advise plz
As I m running a business I have to start investing
For example place rent, some stationery, some electronic items, bills ie web hosting business insurance travel expanse.
Basically £3000 to £4000 expanses .
Could u please guide me how should I do should I transfer some money from the £50 k account to business ac and start spending as my business expanses and keep the recipe of that Expanse's or I should do a directors loan agreement between me and my company if directors lon agreement that should it be done through a solicitor or Accountant or my self any one have any template of such agreement
Thanks