You've been charged. Here's the part before the sentence.
A case exists and nothing is settled. Most of what gets written about federal prison starts at sentencing, which is months or years from where you are. This is the stretch nobody covers: the first 48 hours, and the hearing that decides whether you go home while the case runs.
Where this comes from
I am not a lawyer, and this is the one stretch of the process I did not live. I self-surrendered after my plea. I was never arrested, never sat through a detention hearing, never had a bond of my own. Both pages here are the mechanics, pulled from the statute and from court sources rather than from memory of doing it, and each one says so at the top.
Everything else on this site is written from the other side of it. My conflicts and limits are on their own page, and they are worth two minutes before you take anything here as gospel.
Call a criminal defense attorney. Not tomorrow. The single most useful thing that happens in this window happens before the detention hearing, and it only happens if somebody is there to do it.
Two parts, in the order they happen
If there is no case yet, this is the wrong page
Both parts above assume charges exist. If you have a target letter, a grand jury subpoena, or agents at the door and no indictment, the useful moves are completely different and almost all of them are legal ones.
Where it goes from here
This guide stops at the bail decision. If there is a plea or a conviction, the next thing that matters is the presentence report, and the two audience hubs take over from there.
These pages cover the general rules. Your situation has details they don't. Email me a question. Answers are free, and "you don't need to pay anyone for this" is my most common answer.
I answer in the order received, usually within a couple of days. I have a day job. If your situation genuinely needs more than an email, I take a limited number of consults, so say so and we'll work it out.
Somebody just got the call and has nobody to ask what the next 48 hours look like.