Can anyone give me a basic understanding please?
Easy that mate. Just imagine you've applied for a window cleaning job. Now, lets just say you'd got it...full time employment. Now .....use your imagination......what would you expect ?
As you point out above... what if they're off sick ? Easy that (to say) , you'll have to get a temp substitute.
Yes you'll have to pay holidays, and now the new pension contribution scheme.
TBH you're better off going through the Federation of Small Business forum with a toothcomb. Employing now , whilst easy comes with a whole plethora of red tape and do's and don'ts. PAYE now has to be uploaded weekly to HMRCS, you wil have to register as an employer for Pensions and other stuff... Of course none of this is unsurmountable, it will probably just require more thought and reseach than you envisaged..... i'd guess.
Employee insurance.. risk assesments... etc... Do able, but a head ache unles you're into that type stuff.. that why there is a rise in self employed....working cash in hand..... and franchisees !!!! :-))