Welcome, Joyce! To be fair, it's usually me that bores on about the Archers of yesteryear and I haven't been on this thread much recently.
Robert and Lynda: they moved to Ambridge in the 80s from Sunningdale because they wanted to live a more rural life. They bought Ambridge Hall from the estate of Aunt Laura Archer, a New Zealander who rather improbably came over to Ambridge after the death of her husband, Dan Archer's brother, who emigrated there in the distant past. [This was because the BBC at the time was hoping to sell broadcasting rights to TA to the ex-colonies. There was also a Canadian, Lester something, who was Lilian's first husband and was rapidly killed off when the colonial plan came to nothing.
] Aunt Laura had intended the Hall to go to her friend and lodger, Colonel Danby, but rather improbably didn't sign the will, so it went to relative in NZ who sold it, and Colonel D disappeared from Ambridge. (He was played by Ballard Berkeley, who was also the Major in Fawlty Towers.)
Robert was married before to ?Bobo and his two daughters, Coriander and Leonie, are the product of that marriage. Lynda was his secretary. Not sure if we have ever been told whether R's first marriage had ended before he and L got together - I hope so. R worked in IT. He ran his own business for a long time, contracting I think, and eventually ran into financial trouble and seemed to be unable to return to that line of work. Lynda responded by getting a part-time job as a receptionist at Grey Gables and I think it was after that they started taking in B&B guests. Robert also used to do odd jobs - carpentry and so forth.
Lynda was for a long time still the bossy incomer who the indigenous Ambridgeites (and the incomers who'd been there a bit longer, e.g. Jill) resented. My parents live in a village with a lot of incomers, and I can testify to the realism of this aspect!
Lynda's relationship with Leonie and Coriander has been a bit strained at times but seems to be pretty good now, largely because she is a doting grandmother. Lynda was unable to have children of her own and was sad about it. One of the many things I like about Lynda is that she's mostly used for comic effect but just occasionally we see another side to her. (Of course it helps that Carole Boyd plays the role to perfection. That sniff! I live for the episodes where Lynda sniffs.
)
There! That's my brain dump about the Snells. Hope it helps.