I'd assume it's not easy to apply directly without a reference or prior government work due to the adverse selection problem. You want to make it hard for double agents to get recruited so I assume they have more of a "don't call us, we'll call you" policy.
Since Covid many of them have virtual job fairs.
The clearance is the hardest part. You should be able to find discussions of that online. A major problem is the usual time it takes to get a clearance. Do not expect to have an interview and start in less than a few months.
In the UK and US you have to be a citizen, not sure about other places. You do not need to be native.
It is often easier to start off as a contractor and then get hired.
(I assume she meant fsb.ru, but please use cia.gov since the Russians are rude little shits.)
I strongly discourage you from getting anywhere near those sorts, they're the worst, they will take everything they can get out of you, ratfuck you for shits and giggles, then complain you seem radicalized and try to kill you with a robot.
(Also I'm not in the CIA, I'm just an angry bald man who's good at computers and geopolitics)
They sent back letter written by what looked like a typewriter saying I would have to schedule an onsite interview.