kk I am not sure whether you currently have OFW and is attempting to get CFW so i will go through all the processes.
****IF YOU HAVE OFW AT THIS MOMENT**********
1. (YOU MUST HAVE 5.00 OFW TO ATTEMPT THIS) If you have OFW at this point. download (ChickHEN R2) version in which works for your psp version (1000, 2000, 3000).
2. Follow the instructions on installing chickhen. Once you get chickhen to work on your psp.
3. Download "hellcats flash recovery" the newest version
4. Flash to 5.00m33-6 CFW.
*************IF YOU HAVE CFW ALREADY**********************
1. Update to 5.00m33-6 CFW if you havent already
2. Update to 5.00Gen A
3. Update to 5.00GEN B
4. Update to 5.00 GEN B-2 (GEN B FULL)
5. Update to 5.00 Gen D, then to D-2, then Finally to D-3
***********
O by the way psp3000 have differet cfw versions. its almost the same though
If You have any questions fee free to pm me