Need help installing El Capitan

Hi guys new to this forum ,please can someone help I have a 2010 iMac I know it's old but has served me very well and never let me down until now ,I tried to install elcapitan and erased the drive to do a clean install and I can get past the part where I'm asked to enter my apple account details and I can't get passed that point it says try later and I didn't do a time machine backup .i hope someone can help as I don't want to scrap the Mac .regards Steve

First.. we changed your title as "Please Help" is too vague.

The Apple account details it's asking for is your Apple ID and password. If you're stuck at that point and have no backup, you'll need to do an Internet Recovery which will install your original version of OS X and then you can start over again. Refer to this article and follow directions. And just as a reminder, never attempt an update without first making a backup.

Hi ,I've tried that but I can't enter internet recovery mode ,don't know what else to do

The Internet Recovery should work unless there's something wrong with your iMac or your internet connection. Was the machine running OK before you erased the hard drive and attempted a clean install of El Capitan? Also, Internet Recovery is very slow and does take a while before it starts up. If all else fails, you'll need to take your iMac to your local Apple Store where they can help to get it running or tell you if it needs repairs.

Yeh my Mac was running ok ,it was running the beta version of elcapitan that was when I thought I would install the proper version ,wish I hadn't now .anyway tried Internet recovery but to no avail so not sure shot to do.