hey, i also have a 93 accord. u know that the stock receiver is a 2 din size and since ur alpine is 1 din just go out at buy a dash kit. u can get it from circuit city or best buy for about $20-$40, dont really remember, or u can purchase one online for prob around $20 or so. u will attach that to your head unit/open spot on the car and then proceed w. the install. i could explain how to install it if i were there, but im not so heres the next best thing...
Detailed Head Unit Install for 93 Accord

hope this helps you out....let me know if you need any more help w. this. i didnt use this website when i installed my HU, but i followed the same procedure.

-Raj-