Re: any help or information on building my first
No, you dont need a mobo with dual processor slots, as oh snapword said build it around the I5 3570k and a 7850 (or 7970 if you want to spend a bit more)
8gb ddr3 dual channel 1600mhz ram.
a motherboard ranging from £80 to £200 will be fine.
The psu is where you MUST NOT scrimp, get a branded/trusted psu (corsair,ocz,seasonic or coolermaster)
after market cpu cooler if looking to overclock (which is simple these days with the right motherboard)
regarding motherboards, you need to l;ook at the z77 chipset. (asus, gigabyte or msi)
I5 3570k oc'd 4.3Ghz, CM hyper 212+cooler, Gskill 8gb 1600Mhz, Gigabyte 7970hd oc edition, msi z77a-g45. Samsung 830 256gb SSD, WD cavier black Hdds