How to install a custom ROM on the EVO Design 4G

DISCLAIMER: I am not at all responsible for any of the consequences for what happens after you do this to your phone. You choose to do this, you choose the ROM, you deal with whatever the flaws are of that ROM!
1. Select the ROM that you wish to download. It will have a .zip at the end and will be a 350-900MB file depending on what is in it. You may have to also download the Google Apps file (gapps) to get the Play Store. Most ROMs for the Desire have it built in.
2. Place the file on your SDcard on your phone. You can use the cable to connect your phone to the computer. Create a folder in the SDcard main directory that you can remember. Place the file(s) you downloaded into that new folder.
3. Recovery: Take your battery out your battery. Reinsert it. This will ensure that it is completely off.
Hold your Volume Down button while you press the power button to turn it on. Once on hold on to the volume key (you can let go of the power) until the white HBOOT screen comes up.
Wait as it tries to read your SD card. BE CAREFUL HERE! Volume down (or back up if too far) to RECOVERY. Press the Power button. This will get you into ClockworkMod Recovery
EASY WAY: Download an app to help you reboot into recovery like ROM Manager in the app store. Learn the method above as it will save you headaches later!
4. BACKUP! This is your most important step. If for some reason you do not like this ROM, you can restore it back to where you left it!
Arrow down to backup and restore. Click the power button. Select Backup and click the power button. Get a cup of coffee; this will take 5 minutes or so. If you do not have enough space on your SD card, it will fail. Free up space and try again.
(HINT: If you need to revert, follow the next step to clean the phone out then come back here to select restore (then power). It will give you a choice of dates that you backed up. Select the most recent with the arrow key and power to restore.)
At this point, if you are unsure where the file you downloaded is, jump to step 6 and follow until you find the file (do not click yes!). Then back out.
5. Clean it out: Arrow to "+++Go Back+++" and press power. Repeat until you are in the main menu. Arrow down to "wipe data/factory reset". This will clean out your phone of any left over data that may make the phone unstable. (Don't worry; you backed up right?!)
6. Installing the ROM: Go back to the main menu. Select "install zip from sdcard". Select "choose zip from sdcard". Then choose the menu that you downloaded the ROM to. Find the ROM file and select. It will give you a choice Yes or no.
Select yes and wait. This should take a few minutes. Repeat if you have something else to install (like gapps).
7. The new ROM should be installed! Remember, if you don't like it, you can Restore it back.

Thanks for the instructions , when i was new at all this stuff i almost threw one phone in the wall lol .

Will this work for any Evo Design Rom? Just flash and install the FP apps and everything works?

An addition to this, I believe if Fastboot is turned on in settings, you don't get the Bootloader screen when you hold volume down when turning on the phone.

Make sure to turn off Fastboot in settings before starting this.