Bed and Isa rules ?

Are there any rules I should know about with Bed and ISA ? As I canā€™t seem to find any information on HMRC.

I know CGT is Ā£6000 for this year and I canā€™t fund over Ā£20000 in my isa account.
Iā€™m unsure you can sell a US Stock in a ā€œStakeā€ GIA & then then rebuy the same US stock back in a ISA account? As some sties are saying it need to UK Stocks to do this.

Nightmare trying to get my head around this stuff. Itā€™s not stupidity just always wondering if thereā€™s some hidden rule somewhere thatā€™s been missed. Itā€™s simple really I just want to have an ISA to withdraw in and out of as many times as I want (which probably wouldnā€™t be that many) within the Ā£20,000 limit. Seems to be less interest with free access options though.

Plus some stocks canā€™t be used in an ISA such as ARM Holdings. Seems like thereā€™s always something you have to look out for. Even for brokers apparently some stocks and shares ISAā€™s mistakenly allowed ARM for a while.

I know where your coming from & have been doing this for a few years Stuff like this and finding out how much tax on options trading can be a pain to find out.