Jackie is right -- McConnell's book is a really good one and it's a darned good place to begin!!
I'm going to go back and emphasize some basics here -- we don't know you well, so please don't think anyone is treating you "stupid" (none of this is really intuitive).
To start with -- beagles can tend towards SA. Mine is. That's not even why I say that -- they just tend to be super pack-oriented and tend to have real difficulty being alone. That's not to say you can't train her -- but it is a breed tendency.
First -- you made a bad beginning on the crate and their memories tend to be long. So you have some "un-doing" to do that will lengthen this process. she may have had a bad experience with a crate before you got her!
You **can not** just put her in the crate at this point and go leave her. You will reinforce her hatred of it and set yourself back irrevocably. You must take the time to *train* her to the crate. It's a slow process with the best of beginnings and you have some desensitizing to do at the same time.
So honestly? Right now you may simply need to dog-proof an area where you CAN leave her, and you may want to investigate either some herbal helps and/or you may actually need to get something from the vet in the altnernative. Separation anxiety can get REALLY bad -- to the point of the dog doing huge physical harm to itself in it's panic to try to get out of the crate.
Let me also ask here -- if you got this crate at Wal-mart STOP. Don't use it. Sell it on a garage sale or something but DO NOT use a cheap crate with a separation anxious dog. They can actually bend the crate itself, and open part of it. I've got a dog with separation anxiety (Luna) and she can literally destroy a crate in hours. And she's just a 30 pound basset beagle mix. And her SA isn't super bad any more.
what was said above about the crate being "the BEST" place -- that's critical. So you feed in the crate, you give treats in there, you just plain give treats, toys, food-stuffed Kongs, etc. and anything else you can figure out to reinforce that good stuff happens in a crate. And you DON'T close the door for a long time.
When you do -- you take it micron-sized steps at a time. You close the door while they are inthere involved in something wonderful (like a stuffed Kong) WHILE YOU ARE IN THAT ROOM. i.e., so you aren't 'gone'. Lengthen it slowly -- and simply go in and out of the room.
Never let the dog out when it cries. Even if you have to toss something IN the crate to quiet them for a moment to set them up so they ARE quiet so you *can* let them out.
Be careful not to set up unwitting "habits" that can cue the dog that you are about to leave. We humans LOVE habits -- and things like going to get your purse, or turning the TV on to Animal Planet and then getting your keys out ... those sorts of things tip an SA dog off that you are going to
GASP SHOCK HORROR!!!!!!!!!!!!!!!!!!!!!!!!!!!!
L-E-A-V-E !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
That can send them into overdrive before you even get "See Ya" out of your mouth!
As George Harrison said "It takes time -- a whole lotta precious time ...." (and he was talking about romance not separation anxiety but it happens to fit here *grin*)
If you want to try an herbal -- valerian root works well -- but it takes about an hour if you try to give the ground herb caps. The tincture acts far faster (use the alcohol-free -- it's far more palatable).
Calms Forte is a homeopathic -- and it pairs really well with the valerian. They aren't going to shut the dog down, but they aren't habit-forming either.
I'm also going to recommend a Thunder Shirt -- it's a close-fitting layered shirt that literally helps them feel more calm. It's not a cure all but it IS a help.