1. Where you're named as executor in the will of a deceased person you need to seek a 'grant of representation' ( = 'probate'), which will enable you to collect in the assets of the testator and then to distribute them in accordance with the terms of their will. So the first step is to contact the local probate registry; you can find their details here:
https://courttribunalfinder.service.gov.uk/search/postcode?aol=Probate
Then it's usually just a matter of some form-filling and swearing an oath (or, if you're non-religious, 'affirming') to declare that you've provided accurate information.
2. If the deceased person didn't leave a will then there's a 'pecking order' of people who're entitled to apply for the grant of representation (= 'letters of administration'). The initial form-filling, etc is the same as if there was a will but the estate has to be distributed in accordance with the intestacy laws.
https://www.gov.uk/inherits-someone-dies-without-will
This covers most of what you need to know in either case:
https://www.gov.uk/wills-probate-inheritance/overview
3. You seem to have got that bit wrong as the administrator of an estate doesn't even have to start distributing it until a year has passed!
" . . . a personal representative is not bound to distribute the estate of the deceased before the expiration of one year from the death" [Section 44, Administration of Estates Act 1925].