Congratulations on realizing your dream & your new hobby, & welcome to the Zed world.
Changing from auto to manual is straightforward enough, you've just got to hunt down the necessary parts.
This forum contains the info you need to know.
People are parting out rusty 260 2+2s from time to time, keep an eye out on eBay, Gumtree, this forum etc.
Until you have sourced all the parts for the changeover just keep on enjoying your car, just because it has an auto doesn't mean they don't go well, quite the contrary.