Depends very much on what you want to do....specimen hunting like @Mopedmark for monsters, or just general pleasure angling for bits n bobs, and if a larger fish turns up, hang on and hope..
Firstly you will need a coarse fishing license...these are annual, 8 day or 1 day.....might be worth waiting until you decide to go before getting the annual....... also it would be wise not to invest in a load of stuff before going, cheap stuff is OK these days, as many years ago...Argos was you best bet for stuff and it was worse than useless......i get most of my tackle from Dragon carp direct now (part of sports direct) reasonably priced stuff...not the best in the world, but good enough
it helps if you have someone to take you for the fisrt time (although not necessary) to guide you about things such as line and hook size, type of baits, how to mount them, and even what type of fishing you want to do ( float and Ledger/feeder are the most common, with Pole more "match" focused)
If i was closer to you, i would gladly take you on a day pleasure fishing, as i have plenty of kit to set you up for the day.
you are quite fortunate being in Lincolnshire, as there are plenty of day ticket venues around you (theres a good one up the A1 in Retford....have a look at Hallcroft fisheries .....not the chip shop though!!).
some of the larger commercial fisheries have beginners "have a go" days and you pay a fee, and they set you up with a simple setup to get you catching fish (it was "go fishing" day a couple of weeks ago.)
let me know, or PM me if you want any more help