HD replacement with SSD mid 2007 iMac

I would like to replace my Hd with an OWC 480 gb SSD

I am running a mid 2007 Imac 2Ghz intel core duo version 7.1 with 4gb ram on OS 10.9.5

I am confident I can deal with the hardware side of the install but it's the software side I am not sure about.

I will have done 2 encrypted backups on Time Machine

Once I have done the install what do I do.

I have read that I should simply hit command r and then back up

I do not understand or are familiar with the whole boot or format procedures.

How do I get back to the same OS version and dl my data from time machine.

I require easy simple steps thanks